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Not rendering at FULL cpu capacity?
I recently upgraded from a 2-core, 32-bit Windows PC to a 4-core, 64-bit Windows PC. My intent was to speed up render time, which it did dramatically.
However, when I use Windows Task Manager to see the CPU usage in the middle of a render (video or audio or both), the CPU is operating at 50-70% capacity. Is this normal or can I change a setting/configuration somewhere in my computer or in Sony Vegas Pro 12 to taka advantage of all 4 cores as close to 100% capacity?
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11 Replies
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Maybe your bottle neck is the HDD now? Is it a newer generation internal SATA one? Is it labeled “green” (it means slow)?
Use “Resource Monitor” while rendering to see what is happening.
Also, you can use GPU-Z to monitor the video card GPU utilization. -
There is no setting to increase CPU usage. The computer will give the software whatever it needs. If the software is not requesting more parallel tasks then the computer will have extra unused capacity. Multi-core processing is not like single-core processing; you need to have multiple things that can be done in parallel to use more cores. That’s just how it works. Also using the GPU more will use the CPU less.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
BOTTLENECK WITH THE HDD!!! That’s true…I remember reading about this. So, I should have one HDD for all the source video/audio and when I am ready to render, then output the file to another HDD, right?
I’ll give that a try. I did actually build it with two SATA drives.
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Okay, thanks John. I guess my PC is rendering as fast as possible, then.
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The extra drive will definitely help. Are your encodes faster now? When comparing CPUs, more than the cores matter. Intel Cores are faster than AMD cores, so 4 AMD cores are about 2.5 Intel Cores. However 2 Intel cores today are about 4 intel cores 5 years ago.
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[Heinrich Himmel] “However 2 Intel cores today are about 4 intel cores 5 years ago.”
Just to give a “real world” example of that: my 2008 Mac Pro has 2 x 4 core Intel Xeon E5462 2.8 GHz (8 cores total). My 2012 MacBook Pro has a Intel Core i7-3615QM 2.3 GHz (4 cores / 8 threads). The MacBook Pro scores slightly higher but about the same on Geekbench and they both take about the same amount of time to render projects. That means my 2 year old laptop is actually slightly more powerful than my 6 year old desktop of just a few years ago. So specs alone don’t tell the whole story. Chip architecture plays a significant role.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
The issue is that in both cases, the CPU utilization should be at maximum, for the most efficient encoding. If is not at 100%, there is a bottleneck in some other part of the system that needs to be found.
Usually is a slow HDD (green generation). -
[Sorin Nicu] “The issue is that in both cases, the CPU utilization should be at maximum, for the most efficient encoding. If is not at 100%, there is a bottleneck in some other part of the system that needs to be found. “
If you are rendering with GPU your CPU’s will never hit 100% and there is no bottleneck to be found. If the GPU’s are faster than the CPU’s this is totally acceptable for the CPU to wait for a faster GPU. Nothing to fix.
Also some codecs don’t lend themselves to parallel processing. Those that use long GOP formats cannot simply give a frame to each CPU because each frame depends on the one before it until you hit an I-Frame. Also some plug-ins may be single-threaded and so your other cores will be waiting and there’s nothing you can do to speed it up. Again nothing you can do to fix this.
So there are times when you cannot get the CPU’s to 100% and there’s nothing you can do about it. Some codecs on my system render at 100%. Some never go over 40%. Same system. No bottleneck. Just how some codecs work.
~jr
http://www.johnrofrano.com
http://www.vasst.com -
I would agree, but if you render with GPU and CPU ‘waits’ for the GPU, that that would have to be at 100%.
If none of the CPU or GPU is not at 100%, then probably they both are waiting for the HDD to read and write the file.If that is not the case, then definitely the encoder is not optimized. The higher the video compression, the more paralleling can be done.
For example you can start rendering 1000 slices simultaneously, if all of them start with a ‘I’ frame. -
First, ‘CPU %’ is a bad metric for performance. It can indicate where your bottleneck is. If your CPU is 100%, then it is the bottleneck.
When Windows is ‘waiting for I/O’ as in waiting for a disk driver to buffer some data, the CPU is not busy and is available for other processes. If no one needs the CPU, then your CPU % will be low.
Steve Mann
MannMade Digital Video
http://www.mmdv.com
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