0
$\begingroup$

I need help. My new 3070ti card is giving me VERY SLOW render times with OPTIX. With CUDA it is performing as expected.

I recently upgraded from a 1080ti to a new 3070ti. This site (https://opendata.blender.org/benchmarks/query/?device_name=GeForce%20GTX%201080%20Ti&device_type=CUDA&os=Windows&benchmark=bmw27&blender_version=2.93) is good for comparing rendering times using various GPUs across multiple platforms. Using this, I estimate that an OPTIX render on my 3070ti should be about four times faster than the CUDA times on my 1080ti. Instead, the 3070ti is rendering SLOWER than the 1080ti CUDA - about 80% as fast. I have no idea why.

Does anybody know why this is? As I said, with CUDA the RTX is ok - it's about twice as fast as the GTX. Just not with OPTIX. Do I need to download additional software to get the OPTIX to work as expected? Does it matter what PCIe slot on my mobo the RTX is plugged into (currently PCIe 3.0)? It is admittedly an old board. I've tried both game-ready and studio drivers - same difference.

I'm using Blender 2.93.1 on the last build of Windows 10.

Thanks for any insight.

Improve this question
$\endgroup$
7
  • 1
    $\begingroup$ As far as I know Optix is still underoptimized and not on par with CUDA in terms of performance. From my admittedly limited testing, rendeing on a RTX 3090 with Optix was noticeably slower than with CUDA. $\endgroup$
    – Duarte Farrajota Ramos ♦
    Commented Aug 11, 2021 at 16:47
  • $\begingroup$ Odd. Because the site I linked to seems to imply Optix is much faster for all cards except 1080ti and for most scenes. Thanks for commenting. $\endgroup$
    – Mark Garlick
    Commented Aug 11, 2021 at 16:57
  • $\begingroup$ Tested again right now on my system on a small scene I'm working on. 4:58 for CUDA, vs 3:35 for Optix, it seems you were right. Things seem to have improved since last I tested, though compiling Kernels for the first time took some additional long 5 minutes $\endgroup$
    – Duarte Farrajota Ramos ♦
    Commented Aug 11, 2021 at 19:57
  • $\begingroup$ So Optix was faster for you than cuda. So why not for me? Did you install any additional software to make Optix work? $\endgroup$
    – Mark Garlick
    Commented Aug 11, 2021 at 20:21
  • $\begingroup$ Nope, just the drivers under windows. Try updating yours to the latest version. Make sure no other app is interfering or stealing performance. Check the NVidia control panel or windows for any relevant settings. make sure the GPU is not being "power optimized". $\endgroup$
    – Duarte Farrajota Ramos ♦
    Commented Aug 11, 2021 at 20:28

1 Answer 1

Reset to default
-1
$\begingroup$

I had a similar issue after upgrading my CPU from Ryzen 5500 to Ryzen 5900x, with the same video card (RTX 3060 OC Eagle 12Gb). So after the upgrade rendering in OptiX was incredibly slow (much slower than on the previous 5500 build), and somewhat faster on CUDA. After a pair of restarts of Blender, a few clicks on checkboxes and a couple of test renders, Cycles finally recompiled the cache (Idk how to formulate it correctly), and render times returned back to normal, and of course they got a little faster on the 5900x build, as my weaker 5500 was a bottleneck for the 3060 (CPU was always at 100% load during render, while GP was around 60-70%).

So recalculating the cache on a new build should fix problems like this.

Improve this answer
$\endgroup$
2
  • 1
    $\begingroup$ If I ever have a problem with my renders, from now on I will also keep in mind to try a few clicks on checkboxes... $\endgroup$
    – Martynas Žiemys
    Commented Feb 6, 2023 at 9:48
  • $\begingroup$ As it’s currently written, your answer is unclear. Please edit to add additional details that will help others understand how this addresses the question asked. You can find more information on how to write good answers in the help center. $\endgroup$
    – Community Bot
    Commented Feb 6, 2023 at 10:11

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .