CPU Selection for video encoding

Question

I have been perusing this page: https://openbenchmarking.org/showdown/pts/ffmpeg

Something doesn't make sense to me, I am looking at the following CPU's:

Intel® Xeon® Processor E5-2650L v3 (30M Cache, 1.80 GHz)    
Intel® Xeon® Processor E5-2690 v3 (30M Cache, 2.60 GHz)     
Intel® Xeon® Processor E5-2640 v3 (20M Cache, 2.60 GHz)     
Intel® Xeon® Processor E5-2670 v3 (30M Cache, 2.30 GHz)

According to the benchmarking, the ideal processor is the E5-2640 from that list. I don't see the correlation between the benchmark numbers and the CPU specs, Now the page didn't specify which version of that particular model, so I picked a pretty new one that is almost identical to the newest v4.

I would have assumed that when picking a CPU for video encoding I would be looking the either the:

1. Highest base frequency
2. Largest onboard cache
3. Fastest bus speed

Or some other common metric. What is your experience?

Answer 1

The DV encoder used in the cited test is useless for gauging modern CPUs.

I ran the test command with the referenced media on a 4-core i5 and the difference between -threads 4 and -threads 3 is 0.5% and with -threads 2 is 1%. I see a much larger variance when I use H.264 encoding.

Of course, the bigger flaw is that the command is resizing the video. FFmpeg's internal scaler isn't multi-threaded!

Answer 2

A big question is will your encoder use multithreading.

I have a dual E5-2697 v2 System, 48 Cores.

So if I need to just encode video which does not or cannot, due to effects applied, use the GPU (cuda); then encoding in AE rather than PPro is much faster, as it can thread up to 32 cores, and render much faster.

Otherwise; go with a processor that can be overclocked to the highest level. If your encoder can only use 1 core, you want the fastest clock speed possible... not more cores.