It's a smaller denser core but still incredibly incredibly promising and so so neat.
It's a smaller denser core but still incredibly incredibly promising and so so neat.
iirc, in the 2016 a quadcore intel cpu ran the original crysis at ~15fps
I wonder how many of these you could cram into 1U? And what the maximum next gen kW/U figure looks like.
https://www.techpowerup.com/forums/threads/amd-zen-6-epyc-ve...
EDIT: actually, now that I think about it some more, my characterization of Zen-C cores as the same "idea" as Intel E-cores was pretty unfair too; they do serve the same market idea but the implementation is so much less silly that it's a bit daft to compare them. Intel E-Cores have different IPC, different tuning characteristics, and different feature support (ie, they are usually a different uarch) which makes them really annoying to deal with. Zen C cores are usually the same cores with less cache and sometimes fewer or narrower ports depending on the specific configuration.
Fully agreed, they may be targetting a similar goal, but the execution is so different, and a Intel screwed up the idea so bad that it can really mislead people into assuming that dense Zen cores are the same junk as a Intel E-cores.
AMD's approach was to basically trim the fat on Zen as far as they possibly could but keep the core fast and efficient and you end up with the C-Cores.
In practice (where I generally live with expertise) AMD's approach lets you move software between cores and it generally doesn't care or know, whereas Intel's method applications definetly do care and can have issues.
To me, the difference is moving a virtual machine between two similar CPUs and not having to reboot it (AMDs approach) and having to reboot for one reason or another (Compatibility) -- Intels method.
I've had the same experiences as you with Intel mixed-core desktop parts. They're incredibly difficult to optimize for due to the heterogeneous core mixture, whereas AMD mobile parts are generally more reasonable (you're on a slow core or a fast core, basically), and AMD never made a mixed-core desktop part.
However, Intel server parts several years ago switched to E-core only or P-core only, so all of the heterogeneous core mixture issues aren't a thing - you basically have two separate processor generations being sold at once, which isn't particularly surprising or uncommon.
With AMD server processor families (linked in my comment), depending on the part's density you get either "slow" or "fast" cores and either "wide" or "narrow" units, so you do still have to think about things a little bit there too.
Where Intel really screwed up in general, microarchitecture differences aside, is AVX512. That's the wrench that prevents the same compiled code from running across most Intel parts - they just couldn't decide what they wanted to do with it, whereas AMD just chose to support it and stick with it, even though the throughput for the wide instructions is wildly different between processors.
From the OS side, the change to support it is pretty simple. On the first #UD trap caused by an AVX512 instruction being missing, pin the process to just the P-cores and end the process's timeslice.
AMD's dense-cores are the same microarchitecture, have the same IPC, use all the same instruction sets. The only real difference between them and regular AMD cores is that their dense cores have less cache, and lower peak clocks.
Do they?
I thought it caused very significant problems (when there's switch between E and P core) and they avoided it
But I cannot find anything about it
Yes?
The Intel server CPUs with E-cores, both the current Sierra Forest CPUs with Crestmont cores and the future Clearwater Forest CPUs with Darkmont cores do not support AVX-512 and they are almost identical with the E-cores from Intel laptop/desktop CPUs.
Therefore, for demanding applications you cannot run the same programs on Intel servers with P-cores or E-cores, unless they use dynamical dispatch to select at run-time between AVX and AVX-512 libraries, as the gain from AVX-512 can be very substantial and on server applications not using it would lose money by lowering the throughput.
The Intel Darkmont cores of Panther Lake and Clearwater Forest are almost identical with the Skymont cores of Arrow Lake and Lunar Lake (the main difference is that the Skymont cores are made by TSMC, while the Darkmont cores are made by Intel in their new 18A CMOS process) and they are extremely similar in die size and in performance with the ARM Neoverse V3 cores from the newly launched AWS Graviton5 (which are known as Cortex-X4 in their smartphone variant).
Intel has said that they will eliminate this ISA difference between E-cores and P-cores, but a couple of years might pass until this will reach their server CPUs.
That said, manually disabling AVX-512 on P-cores just so I can have E-cores is still a *bad* tradeoff as far as I'm concerned, but I get that my use-cases aren't everyone's use-cases.