12/10/2023 0 Comments Zen 4 gigThe first most important observation to start with: AVX-512 does help with Zen 4. ![]() Optimizations for these always only yield small additive improvements, where performance improves by perhaps only a few percent (and this is considered an achievement).Īs a reminder: using the test configuration from our regular reviews using the default Handbrake and x265 settings (which leave AVX-512 unused for historical reasons we discussed in the Rocket Lake article), we have found a 7.5-9.0 % improvement in performance at the same clock speed for Rocket Lake after manually enabling the AVX-512. On the one hand, such multimedia tasks can make beautiful use of SIMD instructions, but it’s not like doubling the vector automatically leads to double FPS. ![]() Again, it should be noted that this won’t be some sweeping assessment of AVX-512’s usefulness – as we explained in that previous article, video encoding in x265 isn’t exactly an ideal field for AVX-512 usage. Ryzen 7000, AVX-512 and x265 walk into a bar…īut since we gave Rocket Lake such a hard time last year, we’ll go back to the same benchmark to see how the AVX-512 implementation in Zen 4 performs. Even though it’s not full support yet and AMD opted for a more conservative approach, where Zen 4 uses the old 256-bit SIMD units from Zen 3 to execute most instructions, so a 512-bit operation has to be run through them in two passes (this is also being referred to as double-pumping 256-bit units). You could almost say that rival AMD is now saving this instruction set extension, which Intel had previously touted as its exclusive advantage, through incorporating support for the 512-bit vector extension into their new Zen 4 architecture – for the first time in the history of the competing x86 vendor. It’s been a year since Intel’s pivot from AVX-512 to big.LITTLE and we are in an ironic situation after the release of the Ryzen 7000. The article at the time was simultaneously a tip for users on how to fix this and manually enable AVX-512-using optimizations in x265, and an analysis of what it does to performance as well as power draw. While testing the Core i9-11900K, Core i7-11700KF and Core i5-11400F back then, we found that the x265 video encoder can use AVX-512 to improve performance, but it does not actually do so by default. It kind of sounds like the distant past today, but in the spring of 2021 these CPUs were the very first mainstream CPUs to provide these “next-gen” SIMD instructions to mainstream users outside of the HEDT X299 platform, only to have Intel flip by releasing the 12th generation Alder Lake and take the AVX-512 support back six months later. It was not supposed to be an analysis of how good these instructions were on the then 11th generation Intel Core i9 “Rocket Lake” processors in general. Our AVX-512 test last year happened more or less by accident. Since the now-released Ryzen 7000 processors with Zen 4 architecture also support AVX-512, and there has been a lot of debate about the pros and cons with Rocket Lake, we went back to that test to see how AMD’s alternative implementation fares in it. When Intel Rocket Lake processors with AVX-512 instructions came out last year, we took the opportunity to test how they can improve performance in the x265 video encoder. ![]() A year ago we reviewed AVX-512 on Rocket Lake.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |