ARM Cortex-A73: How a top-end mobe CPU was designed from scratch

Re: Vulnerabilities

Shouldn't make a difference, pipelines stall all the time. The CPU it still executing the right instruction sequence, the probability thing is guessing which instructions to pre-execute to speed things up. If it guesses wrong its wasted a bit of heat.

Re: Vulnerabilities

How about never? Branch prediction isn't something code sees. If the prediction is correct then code executes seamlessly. If it misses then there's a pipeline stall while the correct instructions are loaded and executed. Your code has no sight over or access to the predictor, and it is still subject to the memory management unit allowing it access the code in the first place.

Re: Core alone less than 0.65mm2 in size

128GB of on-chip memory is a tough ask... but I think you mean 128MB.

It seems to me that processors, DRAM, and flash are very distinct segments of the semiconductor market. Maybe because DRAM and flash are highly commoditised and without the volumes that they are sold in, the DDR/flash in a SoC would turn out much more expensive than separate ICs alongside the SoC.

But I suspect that there is a more fundamental reason these 3 strands of technology have not been seen in integrated form.

For your hobbyist requirements, the best solution is a module - and there are some that get close - e.g. Trenz TE0722 which is a 40-pin DIP module with an ARM+FPGA chip (with ADC), boot flash, microSD, but no off-chip RAM.

I reckon flash is not a problem as a second chip, but DRAM requires a lot of interface pins which is probably why it isn't on this module.

Re: How about an octal-core ARM based laptop/netbook?

My wild uneducated guess: It's more profitable to plant a cpu in a phone (or a tablet) than in a laptop.

Windows doesn't play well with arm, that leaves chromebooks. And chromebooks are fine with crouton and linux. So what's your issue with linuxed chromebooks? They are decent hardware i believe.

Re: How about an octal-core ARM based laptop/netbook?

Looking at the power efficiency of ARM vs x86, why oh why don't we have any decent ARM based Netbooks?

I would be interested in ditching Intel too, but I suspect that a more efficient CPU isn't going to make a huge difference in a Netbook, Notebook, Laptop etc, until someone fixes display technology so a backlight is only required in the dark EBook style. Currently LCD based displays try to deal with bright conditions by out-brighting them thus sucking power to the backlight and they always lose when they fight the sun.

It's different for phones because they keep their backlight off and we put it on to view stuff briefly. On a productive computer display, it remains permanently on for hours.

I do have an Intel Celery based Chromebook with a HDMI screen, runs Ubuntu with KDE nicely too, for about 6.5 hours.

Re: How about an octal-core ARM based laptop/netbook?

The Pi3 is quite nice. I have one on my desk. But I also have an Odroid XU4, possibly the best bang for the buck in ARM boards.

The XU4 is $74 vs $35 for the Pi. But it's not actually twice the price, because you have to add at minimum an SD card to both, which is going to cost you a bit for a decent sized fast one. You also have to add a power supply to the Pi, which is probably going to set you back $20+. The XU4 comes with a 20 W power supply.

If you want a headless server to SSH into then you're done. Otherwise, add keyboard, mouse, monitor to both and the price difference starts to look trivial.

Once that's sorted out, the XU4 also has:

- about 2.5x the CPU power in each the main 4 cores (not even counting the LITTLE ones)

- 2 GB of fast DDR3 RAM vs 1 GB

- gig ethernet vs 100

- four or five times faster SD card interface (when used with a good card)

- PLUS an eMMC interface that is twice as fast as the SD card

- USB3 vs USB2

What's missing on the XU4?

- WIFI, Bluetooth, and 3.5mm sound out (but HDMI has sound)

The XU4 competes closely per core with a similar MHz core/core2. Think "White MacBook" of 2008 MacBook Air or something like that. But it's got twice as many (fast) cores.

Re: How about an octal-core ARM based laptop/netbook?

FYI ... There is no "power efficiency of ARM vs x86"

In servers X86 wins hands down on "efficiency" .. even on an equivalent process.

http://www.anandtech.com/show/9956/the-silver-lining-of-the-late-amd-opteron-a1100-arrival/2

And its been possible to make a power competitive X86 smartphone for the past 2 generations

http://www.trustedreviews.com/motorola-razr-i-review

http://www.anandtech.com/show/9251/the-asus-zenfone-2-review/3

Intel's problem is not "power efficiency" ... Its the management, the culture and the inability to cut corners without screwing up !!

Re: Process or Architecture ???

Obviously they decided to not use that last extra 10%...