back to article AMD sued: Number of Bulldozer cores in its chips is a lie, allegedly

AMD lied about the true number of Bulldozer cores in some of its Opteron and FX processors, it is claimed. Mini-chipzilla boasted that, depending on the model, the chips had either four, six, eight or 16 Bulldozer cores. A class-action lawsuit [PDF] alleges the real figures are half that. The troubled California giant is …

Re: Once upon a time...

Ah, the RM 380-Z. The only computer I've ever used that came with a "Cassette Operating System". (I am not kidding: it really did say that on the screen.)

It was a cheap Z80-based microcomputer, sold for insane amounts of money to schools because it came in a ridiculously over-engineered case that was designed to take a direct hit from a British schoolchild, never mind a nuclear missile.

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Re: Once upon a time...Ah, the RM 380-Z

Ah indeed. I had a call from a headhunter about a design job with RM at the time, so I read up one their products first, and then declined to go for interview.

It was as big, heavy and expensive as the industrial computer my company was building at the time. But that had space for up to 3 16-bit processor boards, not one weedy little Z80.

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Re: Once upon a time...

" it's as easy as slotting together a piece of Ikea furniture these days. "

Plumbing's just Lego, innit? Water Lego.

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Colour me ambivalent.

I tend to agree with above posters that the AMD documentation and, even, marketing does explain about the "cores" being in "modules" and that, historically, no FPU is required for something to be designated an FPU so I think the case ought to be dropped.

I actually bought an FX-8120 (I know, somebody had to) and performance-wise it lives up to expectations, though it seems prone to overheating (but no more so when overclocked). I really have no idea which Intel CPU and motherboard combination I could have bought at the time which would perform better for the price since Intel seem determined to this day to produce so many overlapping products with this and that feature enabled or not that it's almost impossible to decide which combination will even support virtualisation never mind will perform the best for a specific workload. Well, until one starts looking at CPUs which cost more than two AMD CPUs and motherboards.

Oh, the reason I am looking at Intel is that I know they do currently make better CPUs than AMD -- I just wish they'd make it easier to choose one.

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Single Precision vs Double Precision

I am a little rusty on my architectures currently, but I believe the single FPU unit is configured with a bit width wide enough for Either full bore calculation at double precision for one core, or two cores at single precision. Which is similar to Intels Hyper threading. OR there was something along the lines for that in reasoning.

Anytime you do double precision floating point the load is going to be higher regardless, FPU's have always been a pricey and complex part of CPU's.Under efficient use other logic calculations and math can be used that are more efficient use of cycles than making pure use of the FPU for some things.

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Re: Single Precision vs Double Precision

Its not really similar to hyperthreading- which is a single CPU masquerading as two cores to try convince software optimised for multicore use- that there are multicores present.

The only legitimate argument- is that there FPU is a bottle neck- however, its only a bottleneck in certain limited circumstances (which might include intensive gaming- or video encoding- but even then, to try and argue its flawed- is a bit mindless- as anyone with a modicum of intelligence will have checked out how the various chips are benchmarked before purchasing- unlike the fool who is now suing the company).

Hyperthreading- itself has a very chequered past- think back to the original P4 and its limitations (I benchmarked a 1.4Ghz hyperthreaded P4 with 2Gb of Rambus- against a 1Ghz P3 with 1Gb of far slower memory- running video encoding software- the P3 won the race hands down- despite the extra memory in the P4 box).

The big issue here is the fool spent 299 each on two processors- without apparently doing any research whatsoever- save looking at the marketing blurb on the box.

As the saying goes- a fool and his money are soon parted...........

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"The lawsuit . . . claims it is impossible for an eight-core Bulldozer-powered processor to truly execute eight instructions simultaneously – it cannot run eight complex math calculations at any one moment due to the shared FPU design, in other words."

Okay, so let's try to understand what this is saying. I am not really qualified in the area of processor design but I can read a sentence good.

It seems to me that the plaintiffs are using the term 'instruction[s]' in a very specific, restricted sense to mean a "complex math calculation" and therefore one that must engage the shared FPU. Unless I am gravely mistaken, however, there are plenty of instructions that would not need to engage the FPU.

In essence, the plaintiffs appears to be attempting to exclude such 'instructions' by definitional fiat. So, one suspects that this case will end up involving rather a lot of complex expert testimony regarding exactly what the definition of a 'core' is.

I have an AMD proc on one of my home PCs, an Intel in the other. An Intel in my laptop and HTPC and an Intel on my work PC. I manage a shed load of servers and there is a mix there (though slightly favouring Intel). SO I really don't support one or the other and, while the chip business is a bit shaky at the moment, I think AMD is vital for a healthy industry - many here will remember the increase in power in Intel chips that came from the competition of AMD.

In the end, I think it would be exceptionally arrogant for any judge to rule that the Bulldozer 'modules' do not in fact contain two 'cores' because to do so would be tantamount to legally defining exactly what constitutes a 'core'. Perhaps some might think that's not so dreadful an idea but I doubt a judge would inclined to do that - especially considering that, as a poster above mentioned, there are plenty of historical processors that had no FPU at all and there is always the possibility that future architectures will structure this relationship differently, as AMD have done.

If you have a legally bound definition of a 'core' then that means processor manufacturers will be forced to design within that definition or risk having their processors viewed as inferior due to having fewer 'cores'. And that has the potential to stifle innovation.

We are seeing a big rise in the importance of GPUs and one can imagine that the future will bring us architectures that meld these two together. What if these new parts don't fit neatly into a legal definition of a 'core'?

Perhaps at that point we may need new terminology anyway, but the point is there - in such a highly technical, continually evolving field, legally defining what some technology or term is runs the risk of more-or-less forcing vendors to fit their research and production into that box.

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"It seems to me that the plaintiffs are using the term 'instruction[s]' in a very specific, restricted sense to mean a "complex math calculation" and therefore one that must engage the shared FPU. Unless I am gravely mistaken, however, there are plenty of instructions that would not need to engage the FPU."

Yes, but it is worse than that.

The Athlon FX FPU is a 256 bits part. It can process ONE 256 bit operation each time. BUT it can process TWO 128 bit operations simultaneously - or even four 64 bit operations!

So, it is a little more complicated than "on FPU equals to one processor" argument. Would he be happier if each core used a 128 bit FPU?

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Pint

Everyone knows

That if you want to do serious math you use a GPU

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Re: Everyone knows

That's, in a way, my point above - that perhaps we are moving towards some hybrid architecture where the idea that a 'core' necessarily must contain a dedicated FPU is not useful anymore.

As a layman - and correction are very, very welcome - I wonder if such a hybrid architecture might have elements of this AMD part, which is to say that the FPU as a component of the CPU could be shared between several cores and used just for those functions and instructions that can't be efficiently offloaded to a GPU-style processor.

The plaintiffs are essentially asking the judge to legally define a 'core' such that it must contain a full, dedicated FPU. To me that sounds a bit restrictive.

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Re: Everyone knows

There is also the precedent of classic SIMD machines such as the Connection Machines CM-2.

In the day it was always referred to as a 64K processor machine (or maybe to the pedants, 64K PEs), had one Weitek FPU per 32 processors, and being SIMD I'd assume there were no per-CPU instruction fetch/decode units.

Oh, and BTW each processor was 1 bit wide...

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Re: Everyone knows

But the instruction set for the 1-bit processors was not too refined. The ide was to have a "computing memory" IIRC. Well, the monograph is still in print... (also: review).

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Re: Everyone knows

"That if you want to do serious math you use a GPU"

Because an MBA is totally useless for even basic math.

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The lawsuit and charge are a lot of crap

At one time, it was common to build computers without any floating-point units at all. By this lawsuit's argument, these computers had no cores at all. And by the way, there are lots of operations that don't require floating point, and it appears that each of what AMD calls a core can independently perform integer operations. So, for such loads, one can, at least in theory, get 8-core performance.

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Re: The lawsuit and charge are a lot of crap

Its a separate specialised core that does maths - the other core does binary. I'd imagine the two are asynchronous (even the 8087 used to go away and work on its own and send an interrupt when its had finished IIRC)

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what about i7

for desktop and mobile version? And less knowledgeable decision makers picking equipment based on the sticker alone.

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Anonymous Coward

"cores" is overloaded

Consider the 512 "CUDA cores" stated on a recent NV GPU and what it really means:

"The idea is that the CPU spawns a thread per element, and the GPU then executes those threads. Not all of the thousands or millions of threads actually run in parallel, but many do. Specifically, an NVIDIA GPU contains several largely independent processors called "Streaming Multiprocessors" (SMs), each SM hosts several "cores", and each "core" runs a thread. For instance, Fermi has up to 16 SMs with 32 cores per SM – so up to 512 threads can run in parallel."

"Only one flow path is executed at a time, and threads not running it must wait. Ultimately SIMT executes a single instruction in all the multiple threads it runs – threads share program memory and fetch / decode / execute logic."

If someone didn't read up and make sure what they were getting is what they thought, then it must not have been important enough for a lawsuit either, eh?

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Not just the FPU

At least Nvidia calls it what it is...to the confusion of many, I might add. And let's don't start about their double precision speed. Joe 6 pack might not care about floats or doubles, but you can bet any scientist does - especially if they're doing neural networks or simulations. Even audio/video editing software often uses floating point extensively these days as the internal format.

At any rate, didn't I read above that in fact there was only one branch prediction unit, one instruction decoder, and so on, per module? (That's what set me off as an old and sometimes forgetful CPU designer) Forgetting the dubiously shared FPU - that to me would mean that most of the time it was really only one thread per module, unless somehow that stuff - which is required to execute ALL instructions, runs at double the speed so it can keep both pipes full....The single copy of the "support" stuff would have to do one, then the other and so on regardless. Maybe it's smart enough to keep feeding one if the other is currently busy for more than a cycle - I don't see that even being discussed.

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APUs and "Compute Cores" muddy the water even more

AMD have recently taken to counting the combined number of CPU and GPU cores as "Compute Cores" when describing their APUs, so for example the A10 PRO-7850B has 4 CPU cores and 8 GPU cores, or 12 "Compute Cores" in total.

Although I'm a little uncomfortable with this marketing-motivated move I do understand the distinction but I'm not entirely sure it's necessary or helpful (which is not to suggest that AMD try to hide the number of actual CPU cores, as they don't). However our clueless, dickhead plaintiff would no doubt sue on the basis that he thought he was buying 12 *CPU* cores - after all, he did overhear someone speaking about CPU cores once upon a time.

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Who says that a core needs to compute independently?

One could argue that there is lots of silicon and how it executes is another story. The fact that they do is a secondary feature. Sure it is important, and most of the time they do execute independently. But consider that there is only one path to external memory (yes, there are caches). If you always fail at cache hits, you will hardly execute instructions "simultaneously". Granted this won't always be the case, but it could happen.

This reminds me of the time when marketing droids touted the number of transistors in a radio (as if more was better), even though they were only being used as diodes, and then of dubious value. In previous incarnations the droids mentioned "tubes" where some were only dropping resistors to work on the AC line voltage (but they did light up!).

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Re: Who says that a core needs to compute independently?

I actually have a microcontroller (to a toy :P ) that has a diode for one special use. To hold the charging cable in place. :D

So I totally agree, number of objects does not guarantee their use is put towards what we want.

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Anonymous Coward

I've done tests using AIDA64 extreme's FPU Julia, mandel, and Sinjulia tests, all with parameters set to use 4 cores for one tests, 8 cores for the other, and the 8 core result was 2x the 4 core result. Running HWbot wPrime on 4 threads vs 8 threads showed a significant difference with the 8 core result at 8.641 seconds on 8 threads vs 12.688 seconds on 4 threads. You may run these tests yourself on a Bulldozer and Piledriver CPU, and you should get similar results. The CPU that was tested is an FX-8320 overclocked to 4.2GHz. This should prove that the CPU does indeed have 8 physical cores, but share resources.

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Strawberry Fields Forever

There's a number of reasons why the lawsuit is total baloney:

#1: A single core is no single core any more, and has not been for a long time.

You see, AMD, Intel and ARM designs have all the same feature: they are superscalar. This means that one core is divided in many "pipelines", up to 8 in the case of Intel Haswell and AMD Bulldozer. Each of these pipeline is designed for a specific purpose: memory branch, floating point op, integer op etc... In many cases, there is more than one floating point pipeline or integer pipeline. So in theory, one core can do up to 8 ops. per clock. In practice it is more around 2 for different technical reasons. Here is a good read on the subject: http://www.lighterra.com/papers/modernmicroprocessors/

#2: Somebody has to define what would be the performance of a legit 8 core CPU.

AMD K10, which is the architecture prior to Bulldozer, was very competitive for its time (2007-2010). Bulldozer is an evolution from K10, because AMD doesn't just start from scratch at every CPU gen they make. When bulldozer was released, in 2011, it had 90% of the performance of K10, when compared at the same frequency and number of core. K10 was limited to 6 core, but bulldozer can have up to 8 cores (4 modules). And now new gen Bulldozer (piledriver, steamroller, excavator) all perform better than the "real" K10 cores.

Trust me. If you buy a $$$$ 18 cores Intel Xeon and think it's gonna game like hell, good luck with the 2.3 ghz core frequency. But afterwards you can always sew intel... right?

#3 The AMD CPUs work and behave just like real x number of cores (2-4-6-8).

On ANY real world or synthetic benchmark, the bulldozer familly of CPUs behave just like Intel single threaded CPUs. One Bulldozer module performs as well as 2 equivalent discrete cores. If you putt a workload on one AMD core and it takes 8 seconds to complete, it'll take more or less 1 second to complete with all 8 cores active. These CPUs perform just like legitimate 2-4-6-8 core parts.

#4 What is really happening

Right now, if you buy a high end (high end in 2012) AMD FX 8350 8 Cores @ 4.0 GHz, you will pay it 169$ :

http://www.newegg.com/Product/ProductList.aspx?Submit=ENE&DEPA=0&Order=BESTMATCH&Description=8350&N=-1&isNodeId=1

Now try to find a intel CPU for 169$ that actually doesn't suck. Nope, sorry, nothing there for you.

Unless you want an i3 4340 dual core... which the same price AMD CPU just obliterates.

AMD never diddled anybody with is bulldozer CPUs. These CPUs always delivered more performance per dollar than any intel option anyways. I hope the lawyers there are also partial time microelectronics engineers. This lawsuit is a total joke. Like a guy in his living room buys two AMD FX 9000 and suddenly becomes an expert in computer science. There are billions of transistors on a single chip. You can not just create a definition of what a CPU core is. In 5 years it's gonna be obselete.

Sorry for the mistakes. I'm not a native english speaker!

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I can dig out both Intel and AMD FPU boards from around 18-19 years ago.

I also have working boards (museum pieces) which I could theoretically demonstrate both boards working sans the FPU units.

If the plaintiff spent 299 each on two processors- as the article suggests- without researching what he was buying- he was a tool and a fool.

I've probably bought a couple of thousand AMD chips in the past 2 decades- over half of which were the legendary K-6-2-500s. People buy AMD chips- as a compromise between price and performance- even these days. Life is a series of choices- when you buy something you similarly have choices. If you choose to buy something without elementary research- I'm sorry- but why the hell is the vendor at fault.

If AMD had hid its chip architecture or blatantly lied about it- he might have a case- they didn't.

Anyone who mindlessly spends hundreds of dollars (or Euros or Pounds- whatever)- without looking beyond marketing blurb- is a fool..........

Lets guess- hard-drive makers and the 'reduced capacity' rather than advertised capacity- are next on his radar......? What a tool.

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Unhappy

Call me cynical

I can't help thinking somebody is backing this guy. I wonder who might want to distract AMD at a critical time?

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Anonymous Coward

Re: Call me cynical

If you are not familiar with the American legal system: There is a thing called a class-action lawsuit.

I expect they lawyers behind this will ask to have this certified as a class action lawsuit, and the damages would be for anyone who ever bought an AMD chip.

As a plaintiff, think of it as a lawyer you never heard of filing a suit on your behalf, without your knowledge, and keeping the damages.

As a defendant, think of it as extortion.

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What constitutes a core?

I was using a high speed bipolar process at the end of the 80's and found a design for 16bit processor that used either 600 gates (or was it (cmos) transistors). I re-modelled it using the bipolar process and it would have been the fastest cpu in the world at the time (we could do 2.4GHz with ease then). Couldn't find any RAM for it thou...

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No chance of a court case like this in the UK.

AMD could have marketed the fpu as additional cores turning the 8 core into a 12 core. Our advertising standards agency probably would have asked them to add the gpu cores too & then banned Intel and others from marketing likewise. It's what they did with ADSL vs Cable, permitting cable to be advertised as fibre whilst banning FTTC being advertised as fibre when the cable offering is essentially FTTC. virgin have never and have no plans to roll out fibre to the home, their system uses coax cable from the cab in the street.

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@Chris17

Virgin are not perfect, but I regularly get 100Mbit/s from our router, whereas from our BT business line we get 8 (and it costs more). If I can get that without having a 30M trench dug in my drive, I won't complain over technicalities.

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Anonymous Coward

Blackadder?

Isn't there a Blackadder Goes Forth where Blackadder is before a Court Martial, and the prosecution brings a private case against the Defence for wasting the courts time? "Granted, Defence counsel is fined for turning up".

In this case, should be plaintiff's .....

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This guy could win.

So they're going to pull twelve regular people off the street and get them savvy enough about CPU architectures and designs to be able to make an informed ruling on this case. And then I'm going to flap my wings and fly to the moon.

This case does have a chance of being successful. Not because it has any merit but because the jury won't have a clue about who is telling the truth.

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Re: This guy could win.

Nope. He might win through twelve regular people and true, but then there will be an appeal. A bit of bad press for AMD for the first bit and a bunch of dosh to pay for the costs on the appeal, but not really a case. (If it did remotely win I suspect Intel would be quaking in their boots because of their varied and somewhat misleading nomenclatures)

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Re: This guy could win.

Nah, they'll bring in an expert witness or two, and after a couple of hours (once he's stopped laughing) he'll set them straight. There's simply no case.

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Caveat Emptor

Someone expecting floating point performance should confirm the performance of what they are buying.

Buying individual CPUs (not computers with those CPUs in them) indicates a certain level of ability that the general public doesn't have (at the very least, replace a CPU in a motherboard) - to replace or match a CPU with a motherboard is not something I would expect the general public to be able to do. And to make his position worse, he bought two CPUs - he MUST have been certain about what he's buying.

I'd also relate this too buying packaged food - if you want to know what is in an item you buy at the store, the only relevant information on the packaging is the ingredients and nutrition information - everything else is marketing to induce you to pick that specific product over a competing product. Buying a food item and expecting it to have X in it (or more commonly now a days, not have X in it), and not reading the ingredients to confirm that X is present (or not present) is caveat emptor in action.

When I have a specific application in mind, I review relevant benchmarking information prior to making a purchase. I wouldn't expect that of someone who's going to do their e-mail, web browse and play farmville, though.

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Anonymous Coward

core has no real meaning in computing only in marketting

Core at best would be read as CPU and as far as I am aware "cores" has never agreed to relate to FPU, cache or any other integrated electronic "organic" system blocks.

The best view of the plantif was that he thought AMD CORES = intel CORES and as neither has officially published their own definition his whole argument is that oranges are not apples. Unless he can prove that AMD said their oranges were exactly the same as intel's apples then he has no case.

he might find they were spoken of as eqivilent but never identical, by the same token if you want some fruit then either are applicable but both have addition benefits ouside of the defintion of fruit.

in summary if he wanted apples then that is what he should have bought

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Not That Bad

The single FPU can still perform one floating-point instruction for each of the two cores it serves simultaneously, as long as that instruction isn't a maximum-width vector instruction. So the only time the matter comes up is when doing AVX instructions - not regular floating-point, not MMX or SSE.

Initially, when I heard about these chips, that wasn't clear from what I read, so I was disappointed, but on learning this detail, I don't think there's a reason to find fault with AMD.

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This smells like an Intel financed taxtic

Full disclosure, I worked at AMD during Bulldozer.

If we get into misleading terminology, how often does Intel make clear that a hyperthtreaded core count is double the "real" core count?

The FPU is shared if there are two threads and us then 128 bit wide. If not shared, it us 256 bit wide. For integer workloads, the smaller fpu doesn't matter. For vector it does and you schedule every other core.

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Re: This smells like an Intel financed taxtic

Wrong. I always knew Intel hyperthreaded "CPUs" showing up under windows as "half as many actual cores" while AMD was always "as many actual, physical cores as show up / claimed". This development certainly blurs the line, but what it also does is shatter my confidence that at least I actually get what it says on the tin with AMD. As a rabid lifelong AMD supporter, this might just be the point where I turn my back and no longer care - something they might have done well to consider before going down this route...

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Will red hat and Microsoft be sued next?

Both report AMD's core count. Conspiracy!!

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Anonymous Coward

Ignorance is bliss

For the clueless, AMD's claims are 100% accurate as to core count. This subject has been beat to death for years and the fact is the core count is correct and yes all cores can process concurrently as has been proven over and over. Bulldozer is not the best architecture in the CPU world but it has it's advantages and disadvantages.

Anyone who doesn't believe that the core count is correct can run Prime 95 or other apps to see all cores loaded and processing individual instructions concurrently. This case will die an appropriate death when it reaches court. In fact this is a frivolous case and the plaintiff should pay all of AMD's legal fees plus a punitive fine as this is a perfect example of technical ignorance leading to a meritless lawsuit.

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Anonymous Coward

You don't buy cores, you buy compute

The consumer is responsible for selecting a machine for their workload. "A core" is not a unit of measurement when it comes to how long something will take to run. Benchmarks, reviews and personal profiling should dictate a purchase. The architecture of a bulldozer core was never hidden from the public. The plaintiff will have to have to come up with an industry standard definition of a core and they won't be able to do this.

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Meh

Well, what exactly is a "core" anyway?

It's implied by the lawsuit that a core is a completely separate processor, but that's not true in anyone's chip, now is it? If you're going to draw the line and equate a core with a complete CPU, then each core should have all of the guts it needs to operate utterly independently of each other core, including power regulation, thermal management, cache, etc. Nobody does this. Perhaps in some ways Intel's chips are somewhat more independent than some of AMD's. But you can't use all of the features of every core simultaneously unless each one has separate buses for for everything and enough intelligent management (including software and the OS) designed to utilize everything in a true parallel configuration. And again, no one on our world does this yet. The way this guy is screaming that he's been victimized, you'd think he bought 4 computers and discovered that 2 of them were just cases filled with sand. (I know silicon is basically sand)

Intel chips have been proven faster in multiple benchmarks. But AMD chips often 'feel' faster to me in real-world use, though this is just one man's subjective opinion.

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8x64bit processors or 4x256bit processors

Is it not the case that these chips are basically 64bit processors, in which case there are 8 core processors. I had thought the fpu's were 128bit, but it seems from comments here that they are 256bit, so the chip is potentially a quad core 256bit processor, or 8 core 128bit unit? It's sold as 64bit and in that mode it runs 8 parallel streams ... end of story?

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E 2

Complete BS law suit. The structure of these chips (1 module = 2 int/logic cores + shared 256 bit FPU and shared decode/cache) was made very plain from word go. This structure was a selling point.

Let caveat emptor prevail: the suit is either malicious or put up by people too negligent to understand what they were buying.

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Unhappy

Confused - help please

I hope you will all allow a very basic question from someone who doesn’t know too much about the differences between AMD and Intel processors.

I have always bought Intel model chips for my PCs. I am a believer in the model which states that you buy the most expensive processor and motherboard and then build your machine around those components, I have never bought or knowing used a PC with an AMD processor chip inside it (and I doubt that I would be able to tell if I did. I have nothing against AMD but that is the way it has worked out for me. We use Intel machines at work, I use an Intel desktop at home and on the go I have an i5 laptop and an Intel Atom tablet.

Ever since I have had MS Vista I have used a gadget which showed me the loading on each processor (not for any other reason than I thought it looked good). When using these gadgets, I noticed that on a dual core machine it showed 4 processors. On the system tab in settings it showed two processors but 4 processors with hyper threading. I had no reason to believe otherwise so I always expected that an AMD chip would do the same (i.e. if it had 4 processors, I would see eight cores due to hyper threading.

Is this article saying that on an AMD processor, if it states 8 cores, the gadget I use would report 8 processors? Do Intel hyper-threads=AMD cores or have I missed the point of this entirely?

I know that this is probably a dumb question but that is how it seems to read to me. Could someone try and explain in plain English for me?

Example:

Is a 4 4.0 GHz core Intel i5 (for example) = 8 core 4.0 GHz AMD

I know this is a bit of a TL:DR but any help would be much appreciated.

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Re: Confused - help please

"Is this article saying that on an AMD processor, if it states 8 cores, the gadget I use would report 8 processors? Do Intel hyper-threads=AMD cores or have I missed the point of this entirely?"

HyperThreading is quite different from what AMD has.

Roughly (very) speaking:

HyperThreading uses parts of the CPU pipeline that are unused, to process another instruction. It doesn't double the performance, but it helps.

AMD went a different road: It made two CPUs, and stripped some parts of one of them. Then both where glued together. Is more complex than this, but...

So. One AMD unit (sold as two cores) has:

One decode unit

Two integer pipelines

One FPU unit

One assemble unit

The catch: It is faster to decode than to process. In most (no all, but most) cases there is no difference from having one or two decode units to two pipelines.

The FPU is 256 bit wide. It can process one 256bits instruction per clock. But it can process two 128bits instructions per clock, or even four 64bits instructions per clock. And not all FPU work is 256bit.

If memory serves me right, the assemble unit goes the same way of the decode unit.

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Re: Confused - help please

Thanks, I think.

time for wikipedia

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Re: Confused - help please

"Do Intel hyper-threads=AMD cores or have I missed the point of this entirely?"

Absolutely not. But for your purposes, basically yes.

In AMD's case, they're actual cores with piss-poor architecture. In Intel's case, they're virtual cores with very good architecture. Intel gives better performance because of the architecture differences. Generally speaking, if you have an AMD machine with 8 cores, it'll be in the same class as an Intel chip with 4 cores (the Intel chip will likely perform about 25% better on most workloads and cost about 50% more).

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FX-8320 user and happy.

This case should be thrown out.

Writing this from a AMD FX-8320. CPU load monitor is showing 8 cores working at various loads. Balanced across the processors. Before purchasing this processor this summer, I did some research. I knew that there was only one FPU per two cores, so the issue is published so there is no surprise about it. I quit worrying about FPU's because much of what I want to do can be off loaded to the GPU's which are much faster.

Looking at a different machine for gaming and debating between a i7 and an AMD. I am leaning towards AMD for cost purposes.

All I know is I am going with and EVGA Nvidia Titan X Hybrid graphics card due to Linux support and got a fantastic buy direct from EVGA.

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