What is the maximum number of threads in x264?

[Z2697]

The processor used in the test above is my old Ryzen 7950X. (16C / 32T)

[Sagittaire]

Originally Posted by FranceBB

You may wanna take a look at my post from earlier on this year: https://forum.doom9.org/showthread.php?p=1999533
To me, however, more than the lack of ability to scale on multiple cores/threads, the biggest downside is the lack of AVX512 which are there for x264 8bit but are missing for x264 10bit.

Well I think that the ability to scale on multiple cores/threads is really higher problem for speed encoding than lack AVX512 compatility.

In the best case, speed AVX512 improvement must be at ~10% for x264 and certainely less in real life encoding scenario.

If you want I have really interessing test for your 52C/112T Xeon to prove that ... ;-)

[LunaRabbit]

Originally Posted by Sagittaire

In the best case, speed AVX512 improvement must be at ~10% for x264 and certainely less in real life encoding scenario.

Did they ever solve the problem with AVX512 causing chips to heat up quickly and throttle? I've held off on buying any Intel stuff for several years now because of that. AVX512 does sound interesting but I've never heard anything good about it. But I don't have many friends running the latest Xeon either.

[FranceBB]

Originally Posted by LunaRabbit

Did they ever solve the problem with AVX512 causing chips to heat up quickly and throttle?

Yes, however in my case we're talking about a very controlled environment, namely a server room, which is not what most people would run those things on. That being said, Xeon are very different from consumer chips. I wouldn't recommend any Intel consumer CPU these days at least given that they seem to be all hands on power efficiency rather than performance and I'm not a fan of the hybrid Efficiency Core / Performance Core approach either. I mean, it makes sense on a laptop but definitely not on a desktop. My personal workstation from 2017 is powered by a 20c/40th Xeon (AVX2 only, no AVX512) and an NVIDIA Quadro P4000, with 64 GB of RAM. It's getting older, but it's still pretty good encoding-wise. Still, with October 2025 getting closer and Windows 10 approaching the end of support, Microsoft would deem such a thing "obsolete" as it only has a TPM 1.2 and not a TPM 2.0 chip. Sure, there are workarounds to get that abomination of Windows 11 running anyway despite the lack of a TPM 2.0 chip, but still this just shows how ridiculous the requirement is...

Originally Posted by Sagittaire

If you want I have really interessing test for your 52C/112T Xeon to prove that ... ;-)

Yeah, I saw the benchmark post and I've been eager to try it, but I have to find a bit of time to do that. Generally those have very little downtime aside from every second Wednesday of the month when I install the Windows Security Updates (yes, I know that Patch Tuesday is the second Tuesday of the month, but it's in U.S time, which translates to Wednesday in UK time).

[Sagittaire]

Originally Posted by FranceBB

Yeah, I saw the benchmark post and I've been eager to try it, but I have to find a bit of time to do that. Generally those have very little downtime aside from every second Wednesday of the month when I install the Windows Security Updates (yes, I know that Patch Tuesday is the second Tuesday of the month, but it's in U.S time, which translates to Wednesday in UK time).

In fact for your monster Xeon, you need particular benchmark version.

Certainly with 8 simultaneous mulipart encoding scession to saturate your 56/112 thread CPU.

I can make really particular benchmark to show the multipart encoding interest.