The Intel 12th Gen Core i9-12900K Review: Hybrid Performance Brings Hybrid Complexity
by Dr. Ian Cutress & Andrei Frumusanu on November 4, 2021 9:00 AM ESTCPU Benchmark Performance: E-Core
In this batch of testing, we're focusing primarily on the E-cores. Intel claimed that the performance was around the level of its Skylake generation of processors (6th Gen to 10th Gen, depending which slide you read), and we had to put that to the test. In this instance, we're comparing to the flagship Skylake processor, the Core i7-6700K, which offered 4C/8T at 91 W. We also did a number of multi-threaded tests to see where the E-cores would line up.
In order to enable E-core only operation, we used affinity masks.
Single Threaded
In these few tests, we can see that the E-core is almost there at 4.2 GHz Skylake. Moving down to 3.9 GHz, perhaps something like the i7-6700, would put it on par.
Multi-Thread Tests
Having a full eight E-cores compared to Skylake's 4C/8T arrangement helps in a lot of scenarios that are compute limited. When we move to more memory limited environments, or with cross-talk, then the E-cores are a bit more limited due to the cache structure and the long core-to-core latencies. Even with DDR5 in tow, the E-cores can be marginal to the Skylake, for example in WinRAR which tends to benefit from cache and memory bandwidth.
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mode_13h - Tuesday, November 9, 2021 - link
Well, AMD does have V-Cache and Zen 3+ in the queue. But if you want to short them, be my guest!Sivar - Monday, November 8, 2021 - link
This is an amazingly deep, properly Anandtech review, even ignoring time constraints and the unusual difficulty of this particular launch.I bet Ian and Andrei will be catching up on sleep for weeks.
xhris4747 - Tuesday, November 9, 2021 - link
Hiricebunny - Tuesday, November 9, 2021 - link
It’s disappointing that Anandtech continues to use suboptimal compilers for their platforms. Intel’s Compiler classic demonstrated 41% better performance than Clang 12.0.0 in the SPECrate 2017 Floating Point suite.mode_13h - Wednesday, November 10, 2021 - link
I think it's fair, though. Most workloads people run aren't built with vendor-supplied compilers, they use industry standards of gcc, clang, or msvc. And the point of benchmarks it to give you an idea of what the typical user experience would be.ricebunny - Wednesday, November 10, 2021 - link
But are they not compiling the code for the M1 series chips with a vendor supplied compiler?Second, almost all benchmarks in SPECrate 2017 Floating Point are scientific codes, half of which are in Fortran. That’s exactly the target domain of the Intel compiler. I admit, I am out of date with the HPC developments, but back when I was still in the game icc was the most commonly used compiler.
mode_13h - Thursday, November 11, 2021 - link
> are they not compiling the code for the M1 series chips with a vendor supplied compiler?It's just a slightly newer version of LLVM than what you'd get on Linux.
> almost all benchmarks in SPECrate 2017 Floating Point are scientific codes,
3 are rendering, animation, and image processing. Some of the others could fall more in the category of engineering than scientific, but whatever.
> half of which are in Fortran.
Only 3 are pure fortran. Another 4 are some mixture, but we don't know the relative amounts. They could literally link in BLAS or some FFT code for some trivial setup computation, and that would count as including fortran.
https://www.spec.org/cpu2017/Docs/index.html#intra...
BTW, you conveniently ignored how only one of the SPECrate 2017 int tests is fortran.
mode_13h - Thursday, November 11, 2021 - link
Oops, I accidentally counted one test that's only SPECspeed.So, in SPECrate 2017 fp:
3 are fortran
3 are fortran & C/C++
7 are only C/C++
ricebunny - Thursday, November 11, 2021 - link
Yes, I made the same mistake when counting.Without knowing what the Fortran code in the mixed code represents I would not discard it as irrelevant: those tests could very well spend a majority of their time executing Fortran.
As for the int tests, the advantage of the Intel compiler was even more pronounced: almost 50% over Clang. IMO this is too significant to ignore.
If I ran these tests, I would provide results from multiple compilers. I would also consult with the CPU vendors regarding the recommended compiler settings. Anandtech refuses to compile code with AVX512 support for non Alder Lake Intel chips, whereas Intel’s runs of SPECrate2017 enable that switch?
xray9 - Sunday, November 14, 2021 - link
> At Intel’s Innovation event last week, we learned that the operating system> will de-emphasise any workload that is not in user focus.
I see performance critical for audio applications which need near-real time performance.
It's already a pain to find good working drivers that do not allocate CPU core for too long, not to block processes with near-realtime demands.
And for performance tuning we use already the Windows option to priotize for background processes, which gives the process scheduler a higher and fix time quantum, to be able to work more efficient on processes and to lower the number of context switches.
And now we get this hybrid design where everything becomes out of control and you can only hope and pray, that the process scheduling will not be too bad. I am not amused about that and very skeptical, that this will work out well.