will CPU upgrade gain anything if using iray card renders

alan bard newcomer

I render on my card... and it seems that daz never really uses my dual xeons to any degree. 
But since I can get about a 60% performance increase with a replacement pair at about $300
I'm wondering if it will gain me anything in pushing items around the viewport 
and any gains in cutting g-8 loads down from 3 minutes?

 

Richard Haseltine

Probably not - if the actual speed of a single thread has increased that might have an effect, but core count won't affect loading (or much else that doesn't use the GPU).

nicstt

As long as your current CPUs are not causing bottlenecks for the GPU, then no.

There is a caveat: dropping to CPU rendering is likely to see an improvement.

ebergerly

You can see what your CPU's are doing during a render, or just while using D|S and navigating the viewport. Just fire up Task Manager (if you're on W10), and under Performance click on the CPU, and you can see what all the cores/logical processors are doing in real time. Usually what happens is D|S loads the scene into system RAM so it can work on it, and the CPU is a big part of that. Once you hit Render, the CPU gets very busy with all cores to change that scene data into a smaller set of data in an Iray format, which it sends to the GPU's. Once it sends that Iray data to the GPU's, the only thing the CPU has to do is get data back from the GPU to update D|S and the 3D viewport and the render viewport and update render status. If you watch the CPU's threads during an Iray render you can see intermittent activity on the CPU cores, and maybe one that's working full time. But certainly not stressing the CPU in any way, and it's not something that more cores would help.