3 ms·
They went from 4 to 5 decoders. Rather than 1-2 complex decoder and a few that only work on simple instructions, every decoder can now decode everything, I-cach
by hajile 4y ago
They went from 4 to 5 decoders. Rather than 1-2 complex decoder and a few that only work on simple instructions, every decoder can now decode everything, I-cache handles fusion.
This all happens with a 75% reduction in decoder size due to dropping more complex 32-bit encoding. As the decoder is always on to feed the speculative execution, this is undoubtedly a substantial decrease in power consumption.
x86 decoder is 8-10% of the total die area. If they could reduce that to 2%, that would represent 6-8% smaller core size and at least 6-8% reduction in power consumption (likely more as other areas will stay power-gated much more of the time).
This is a more general point. X2 in the Qualcomm 8cx gen 3 beats Zen 1 desktop chips and is rather close to Zen 2 U-series chips in single and multicore geekbench scores. It uses 7-10w peak while those U-series use 30-50w peak which is why despite so much battery being used for stuff like wifi and the screen, thin and light laptops with the 8cx have generally gotten 2x the battery life.
I wonder how many of these ARMv8/9 chips will have to beat x86 in all these metrics before people will finally be convinced that ISA really does matter (or both AMD and Intel are utterly incompetent). Maybe it will take Intel finally releasing a RISC-V chip to change minds.
- de6u99er 4y agoI also believe that RISC-V is the future. It would be great to have implementations that can compete with ARM at least CPU wise first. Then we will need GPU's and eventually co-processors which are optimized for IO, media, machine learning, ... to create the full package. Also a new memory standard would ve great because I don't see on-chip memory being economic like Apple is doing it right now.
- pjmlp 4y agoUntil software that does matter gets ported over to ARM.
- rbanffy 4y agoWhat prevents me from getting an ARM laptop with higher end SoCs is Linux support. I can install Ubuntu or Fedora immediately when I buy pretty much every x86 laptop and expect everything to work, but I am not as confident about ARM laptops (PineBook family excepted, but they have some limits). Having manufacturers come forward and offer fully supported mainlined Linux models would work wonders.
- bpye 4y agoI wouldn't be surprised if Apple's ARM MacBooks get there first. A lot of hardware works already, and it seems like there has been a lot of progress on the GPU too.
- rbanffy 4y agoI don't find that very appealing. MacOS is a good Unix and I only start Linux containers on it when I'm testing something specifically for Linux (which I usually consider a bug - the software I write should run well on anything Unixy enough).