GPU, CPU, and Render Times

DarkRepast

Hello,

So I've been setting up some renders lately that are just taking forever. Not even very complicated, just a model (or 2) and a setting. I've tried Light it Up 2 and Dramatica as my sources. Whether I throw in additional lights, like the Real Light shaders or otherwise, my renders are going forever (I just had one go for 3 hours that got to 3%).

I turned to the advanced properties where it showed I had CPU and GPU selected. For an experiment, I've unselected CPU and hit go. It's STILL topping out the CPU 100% and seems to be going just as slow.

Should both be selected? Should it be tapping my CPU still? What's the optimal setting? 

I have a GTX 980 Ti, i7 and 32 gigs of RAM. 

evilded777

I'd say you are maxed on VRAM for some reason and the renderer is falling back to CPU.

 

Something is eating all your VRAM.  How much do you have on that card? Probably 2 GB or less... could be lots of normal maps.

fastbike1

@evilded777 "Something is eating all your VRAM.  How much do you have on that card? Probably 2 GB or less... could be lots of normal maps"

A GTX 980ti is 6GB Vram

evilded777

fastbike1 said:

@evilded777 "Something is eating all your VRAM.  How much do you have on that card? Probably 2 GB or less... could be lots of normal maps"

A GTX 980ti is 6GB Vram

Well then... either its a REALLY big scene, or something else is wrong.

fastbike1

As is often the case w/ Iray , I suspect the lighting is an issue. Real Lights from DZFire are mesh lights, which tend to be slow in Iray. Also, a "couple of figures and a setting" can be deceptively high for Vram depending on whether there is a lot of SubD, HD morphs, complex hair, etc.

The output resolution also matters. Render settings with high convergence or quality settings higher than 1 will also eat time. Render Quality settings are geometric (roughly double the previous time). Adding more light (brighter, not necessarily more lights) will drastical reduce render time. If you want the scene dimmer, do that with Tone Mapping in Studio or in post processing. Still, the CPU shouldn't be maxed.

However, I think something else is going on. My system is a I7 4770K, GTX980TI, 32 GB ram. The attached file rendered at 6000x4000 in 2.5 hrs. with Render Quality 1. ~2400MB Vram. CPU was @ ~27% with several Internet Explorer tabs open during the render.