OTOY Forums

Hi,

I installed a GTX 1080 ti and hope to see a super speed, but the GPU isn't full used. Why is there no nearly 100% usage?

-Micha

I saw that on my network machine, around 85% - not sure if maybe 1080ti counted in the facts you can work better in your viewport now cause it feels easier to work on 1080ti as primary gpu.. maybe it's optimisation, still it's faster by 30% than 980ti..

it's actually pretty normal, but please run OctaneBench & post result You get. 1080Ti scales from 160 to 220, but mostly average between 180-190.
once we will have Your results, I can help to squeeze more performance.

The result is 179.5. But my impression is that it is not a question of the GPU power. Independent from the GPU power nearly 100% should be used. At other scenes it works quite good, but at the current scene the usage stays low. What could cause the slow down?

Fine, the benchmark shows the same issue. So, it seems to be not my Rhino scene and maybe it's easier to find the reason.

your result is perfectly fine.

in most case (depending on the scene) load is going to be between 70 & 90%. In order to maximize that, You need fast CPU (for instance I run flat 4Ghz on 6core) & turned out C states. Once Your CPU clock stays optop, it reacts faster to those "calls" from GPU to send information.

Another thing is GPU frequency itself. Adding about 200 for core + 500 for memory, can boost render results about 20% (I'm getting over 220 in OctaneBench with 1080ti, that scores ~ 180 out of the box). However to keep stability You might need to bump fan speeds or even go watercooling route.

Last but not least, if You're rendering in PT, there are couple of parameters in Path Tracing: Parallel Samples (8 by default) & Max. Tile Samples (16 by default) - crank those to max & Your GPU usage will increase about 5%.

Overall tuning for performance is not that hard, but nvidia done a great thing balancing compute performance with acoustic signature of GPUs, so they would make little to no noise under full laod. If You do not care about that or have aftermarket cooling system, then squeezing 95% under full laod is possible.

I started the benchmark again and observed the CPU - never above 4%. Maybe it's a software bottle neck for Dual Xeon machines. I hope the Otoy team will find a solution. During the benchmark my card stay quiet&cool. I thought benchmarks stress the hardware.

I will try the GPU overclocking.

Thank you for your hints.

CPU load it's not a bug, but a feature. Actually running 100% load on CPU in parallel to OctaneBench actually increase result as well, since CPU is busy & keep higher clock speeds.