Re: Rooting for AMD here
"FPU wasnt the only thing shared between cores; the penny pinching design crippled the stupid things in many real life applications."
You're correct, but sharing components between cores wasn't the major issue.
As you note, gen-1 FX's needed around 50% more clock speed to achieve the same performance as Phenom II chips for many workloads. This was because AMD focussed on frequency scaling rather than IPC. The design scaled to ~8GHz (with liquid N cooling...) far exceeding the scaling of other processor designs, but IPC was much lower.
AMD's assumption was that higher frequencies and more core cores with more functionality would beat IPC and the less capable hyperthreading. The reality was that they made a lot of mistakes, effectively eliminating a lot of the things they had done well in the past (cache and front end efficiency) while ignoring the things they did badly (microop retirement, IPC, AVX/AVX2). While it was a learning experience that almost bankrupted AMD, it appears to be paying dividends with Zen - they have learnt from their mistakes.
Combine the design decisions/design errors with Global Founderies taking a long time to have decent 32nm process design rules and you have a lot of pain for AMD for the 4-year lifetime of the Bulldozer core and its variants.
Biting the hand that feeds IT
