GPU ray trace hundreds of times faster than CPU?

[Ericbowen]

There are so many variables which equate to considerations with a workflow that decide the threading and performance of CPU’s and ram with AE. You have to be careful with the information you gather because workflows are as different as flavors of ice cream and that means the ideal specs for you will be different to some extent.

1. CPU is most important factor for AE and remains so regardless of workflow. However what CPU is best for you is based on codecs of media used, FX used, and complexity of the comps. AE does thread very well by itself. However some codecs do not thread as well. Those will use ideally 8 to 12 threads and sometimes 16 and then GHz decides performance from there. Those codecs are normally Mpeg based such as AVC or Mpeg 2. Then codecs such as Red, DNG, AVCIntra, and most sequence of still based formats thread very well and will use almost what ever threads are available. You can sacrifice some GHz here but don’t go below 2.6GHz on any CPU. That is where the performance really suffers for any editing application. If you get a 6 Core you want 3.4GHz or higher and preferable 4GHz or higher. 8 Core can normally provide the performance boost at 3.6GHz or higher. Keep in mind Complexity of that comp ie layers and activity will add to the ideal threading requirement. The more complex the comp the more threads you need for ideal performance with ram preview or export. The codec that you export to can and will limit the threading though so keep that in mind if you see an export not thread well. Some FX don’t thread well either so if you see a poor threading export check your FX used.

2. Ram – you really want a minimum of 32 GB of ram for AE on most workstations. However you have to provide enough ram per thread to feed the cores the frame data. That normally equates to 2GB of ram per thread but atleast 1.5GB per thread needs to be available. If you get a Dual Xeon system then you absolutely will require more than 32GB of ram because of the amount of threads you have. otherwise you waste all of the extra processing power 2 Xeons give you. So if you get 2x 8 Core Xeons you need bare minimum 32GB of ram just for AE and not counting Windows or Graphic buffering. So that means you want 64GB of ram. Complexity once again raises this amount. The more complex the comp on average the more data per frame that has to be accounted for. That means you may need to raise that 2 GB per thread to 4GB per thread. Only you know how complex your workflow is. To give you an example, my 1 min AE comp with 64 layers takes 56GB of ram just to export with multiprocessing on. That is all 1080 frames as well with nothing in the 2K or higher range. That also raises the ram amount per frame.

I hope this helps with the overall things to consider with specs. The comments on the GPU’s having far less effect in AE are absolute. Also Walter is correct on the Quadro card. Don’t get that unless you need 10bit color preview and have a 10bit color workflow with monitoring ability. Use the money spent on that to get faster CPU’s. Don’t get any CPU under 2.6GHz no matter how many cores it has. Also make sure you get enough ram for the CPU you decide on.

Eric-ADK
Tech Manager
support@adkvideoediting.com