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Skylake1

When Intel launched the Skylake-X platform, it communicated to reviewers the chips would take a bifurcated AVX-512 strategy. The Core i9-7800X and all the multicore chips above that point supposedly had ii AVX-512 units, while the Core i7 CPUs in the Skylake-X family only had i. Kaby Lake-X CPUs didn't have whatever, simply we're not sure if anyone ever actually bought a Kaby Lake-X CPU, and and then the much-more-appealing Core i7-8700K replaced it as an overall recommendation.

At any charge per unit, the point was clear: If you wanted full AVX-512 capabilities, you had to buy a 10-core or higher CPU. Except Intel is now telling people that's non true. All Skylake-X CPUs accept access to 2 total AVX-512 units.

SKLServer

Intel has since updated its own Ark.Intel.com website to confirm this. Tech Study notes hardware testers who bought Skylake-X CPUs after they were released last fall had posted figures that seemed to point a full 2 AVX-512 units were operational. I'm a bit embarrassed to admit information technology, but I actually saw the same threads when I was working on my Cadre i9-7980XE review. Saw them — and decided that they must either be mistaken, or that another consequence was goosing the results. One thing we discussed in the 7980XE review was that nosotros had trouble getting our CPU to behave in the manner Intel specified. Given that AVX-512 imposes a pretty hefty clock penalty, it seemed reasonable to think a CPU without that penalty might plough in much higher numbers, even if it had two AVX-512 units. I didn't have time to dig deeper into the state of affairs in the hectic "This thing has to exist published in six hours and the only thing I've written is a cord of curse words" that often defines reviewing, but I do apologize for the mistake.

There's two ways to look at this situation. If you've wanted to programme AVX-512 and were concerned virtually only having 1 AVX-512 unit to work with, you tin can now purchase a lower-end Skylake-X product with no business concern on that front end. On the other hand, anyone who bought a more than expensive CPU specifically for AVX-512 is unlikely to be pleased to discover there was no reason to spend the extra cash.

Intel may bring AVX-512 to its ordinary desktop CPUs with Cannon Lake later this year, but information technology'southward not clear how important the characteristic volition exist to consumer workloads. Intel's AVX improvements over the years accept typically been aimed at the HPC market. While in that location are consumer applications that accept advantage of them, we haven't seen the kind of general speedup that informed the shift from x87 FPU code to SSE2. The clock penalty that AVX-512 equipped CPUs accept when using the SIMD instruction set could also create scenarios where it'south more expensive to apply AVX-512 than conventional AVX. AMD'south Ryzen has proven stronger than we thought when it comes to FPU functioning, despite the fact that Ryzen only uses 128-bit registers for AVX compared with Intel's 256-bit registers.