Video rendering; is CPU, GPU, or RAM more important?

[CursedLemon]

I'm looking into what I should buy next to make my video exporting a little smoother. I don't do any major video editing, but I would like to make my renders as fast as possible.

Right now I have a GTX 260, 8 gigs of 1333 RAM, and an i7-875k processor. None of these are overclocked just now, but I figure I can fiddle with that sometime.

[LigH.de]

A powerful CPU with several cores and highly parallel instruction sets (SSE4, AVX2) will be your most important investment to avoid a bottleneck. While x264 scales well on many cores, the efficiency will drop when encoding is spread across too many, though. HEVC encoding with x265 has even more dependencies limiting the parallelizability; but you may be able to run a few separate encoding jobs at the same time.

If you need at most AVC (H.264) with up to FullHD (or maybe 4K) video, your RAM will be enough, just try to find a fast model. If your target is certainly HEVC and UHD, more will be better.

The GPU won't help you much. Even though it is possible to have a GPGPU with many cores calculate video, the instruction set and the general architecture of GPGPUs are not exactly made for the needs of efficient video compression; until today, there is no GPGPU really competitive with software encoders when it comes to a good relation between speed and quality, called "efficiency": As fast as they can be, as low is their quality retention, due to the low complexity (comparable to Baseline Profile only). The intel QuickSync encoder appears to be slightly better than more typical gaming GPUs.

[CursedLemon]

A powerful CPU with several cores and highly parallel instruction sets (SSE4, AVX2) will be your most important investment to avoid a bottleneck. While x264 scales well on many cores, the efficiency will drop when encoding is spread across too many, though. HEVC encoding with x265 has even more dependencies limiting the parallelizability; but you may be able to run a few separate encoding jobs at the same time.

If you need at most AVC (H.264) with up to FullHD (or maybe 4K) video, your RAM will be enough, just try to find a fast model. If your target is certainly HEVC and UHD, more will be better.

The GPU won't help you much. Even though it is possible to have a GPGPU with many cores calculate video, the instruction set and the general architecture of GPGPUs are not exactly made for the needs of efficient video compression; until today, there is no GPGPU really competitive with software encoders when it comes to a good relation between speed and quality, called "efficiency": As fast as they can be, as low is their quality retention, due to the low complexity (comparable to Baseline Profile only). The intel QuickSync encoder appears to be slightly better than more typical gaming GPUs.

Awesome response, thanks so much. Well, I think I have one of the better processors for the LGA1156 socket type, unfortunately, unless I wanted to get one of those "extreme" models.

[aymanalz]

Awesome response, thanks so much. Well, I think I have one of the better processors for the LGA1156 socket type, unfortunately, unless I wanted to get one of those "extreme" models.

@ligH.de has given a good answer. I'll give you the tl/dr version: Get the fastest multicore processor you can. Preferably haswell or above, since they have AVX2.

[LiamKemar]

I'd never heard of, but their methodology seems sound.For any productivity software, a better CPU will benefit you over a better GPU,rendering you need more cores.

[SameSelf]

I agree with the above. CPU reigns supreme when it comes to rendering. I have 16 GB. When I render, memory usage will increase maybe 0.5 GB while the CPU usage will spike to 100% for the entire time it takes to encode. Although 16 GB is nice because I can nuke Windows Virtual Drive and still have Premiere Pro, After Effects, Photoshop, and Encore all open at once without a problem.

But, imo, if you are itching to upgrade and you have enough budget, I would wait for Skylake, which will be out sometime this year for traditional desktops per Intel's latest leaked roadmap.