New i7-9700K vs i9-9900K for x265

[paulanderegg]

Looking to build new PC to replace an old Ivy Bridge system. Looking at either the i7-9700K or i9-9900K...basically same chip, one with hyper threading, one without.

For x265 HEVC transcodes, would the hyper threaded in the 8 core i9-9900K add any meaningful transcoding speed advantage over the 8 core i7-9700K? By meaningful, I mean at least 10-15%+. If not now, would it be probable that updates to HB in the next few years might leverage the extra cores and threads more effectively?

The search tool brought up returns for diminishing returns for anything over 6 cores on x264, and lower quality the more threads you throw at a transcode. I figured many might be asking the same question about these new chips, so I am asking here for opinions.

Paul

[s55]

Depends on a number of factors, it certainly won't be significantly faster going from non-hyper to hyperthreading. At best maybe 15%. At worst, it could slow down a little (but you can usually turn it off in the bios if it had a negative impact but that's more an edge case)


Either way, It's not worth a substantial increase in price imo.

[rollin_eng]

First CPU choice will not effect quality.

As far as which CPU the newer one will probably be faster but as far as bang for buck you generally better off going for one or 2 generations old chips.

[paulanderegg]

So my i9-9900K arrived today. Testing with Hyperthreading on, 8C/16T, resulted in 5.7fps for the 2 minutes test run. Turned off Hyperthreading, to emulate an i7-9700K 8C/8T, and the same 2 minutes test run resulted in 4.5fps. So looking at a roughly 25% increase in encoding speed in HEVC by just throwing more threads at Handbrake. Was almost expecting a null difference, given the posts that indicate handbrake doesn't do much with more than 6 cores/threads.

Package power at 8 threads was 120watts vs 180watts with 16 hyperthreads...65C vs 85C for 8 vs 16 thread also.

Paul

[BradleyS]

The 6-8 core point of diminishing returns applies to the x264 encoder. x265 scales out many cores.

[mduell]

given the posts that indicate handbrake doesn't do much with more than 6 cores/threads.

Widely misunderstood.

For a DVD with no or single threaded filtering, sure, maybe, but not for HD content and reasonable encoder settings.

Also diminishing returns doesn't mean no improvement, it just means its something less than perfectly linear.

[paulanderegg]

That is why I am posting this update, as that 6 core "info" seems to come up when you google around for high core count advantages in Handbrake. I am happy I got the i9-9900K, and for "only" $520 out the door shipped.

given the posts that indicate handbrake doesn't do much with more than 6 cores/threads.

Widely misunderstood.

For a DVD with no or single threaded filtering, sure, maybe, but not for HD content and reasonable encoder settings.

Also diminishing returns doesn't mean no improvement, it just means its something less than perfectly linear.

[cturtle97]

Sweet. Does anyone know if handbrake supports faster encoding with GPUs? I’m trying to encode my Blu-ray collection with an older i7 laptop. I have good SSDs in it. I want everything to be high quality 1080 so I can stream to my big 4K tv with Plex. It currently takes 5-9 hrs per movie. Looking to purchase or build a good desktop to speed this process up. Didn’t know if a higher end GPU would be worth the money. I’m not a gamer (no time) so wouldn’t really need one otherwise. Looks like I will go the i9 route given this post.

[paulanderegg]

Handbrake can see my Nvidia GPU, and shows options for Nvenc h264. It's insanely fast on my GTX 1080 Ti...I mean like INSANE fast!

Paul

[Woodstock]

Yes, but is it efficient, in terms of size and quality? I stopped using QSV because I'd rather have the smaller files and better quality of x264.

[paulanderegg]

You get all the controls of a normal CPU encode with the Nvenc option...I just played with the fast setting and it burned through at like 200+ frames per second. I wasn't really looking at the quality, because I use CPU for quality. The forums tend to indicate the Nvenc is not as good as Quicksync, which is not as good as CPU.

Paul

[mduell]

Yes, but is it efficient, in terms of size and quality? I stopped using QSV because I'd rather have the smaller files and better quality of x264.

No, it's just fast.

[cturtle97]

Thanks guys.