Cycles building BVH suddenly gone hyper slow

Hello.

I was using Blender about 3 weeks ago and it was all fine. Last week I lost PSU, so I meanwhile bought different gpu (better one). But I noticed Blender now builds BVH a lot slower.
Back then I had building for 3-5 seconds when I had a simple character. Now I wait more than one minute.
I saw that first time when I was using onboard gpu. I thought it’s because somehow CPU gives it’s calculating power to GPU, but no.

I haven’t changed the Blender version in time of waiting for new PSU, nor installed new software.
Could someone help me? I’d hate to be ignored for the 3rd time in a row. :expressionless:

Hi, the problem is nobody can reproduce it without a test file.
Good would be also system specs with driver and Blender version, OS and so forth.

Cheers, mib

It’s Windows 8.1 (it’s not updated since one update was always crashing) 64bit. With newest graphic drivers for Nvidia (both previous GPU, integrated GPU and actual GPU were Nvidia so I didn’t had to reinstall it).

I have tried turn off in Blender the Spatial Splits and it started to buld BVH with normal speed. It’s kinda awkward, because it’s suppoused to speed up building BVH :smiley:

Problem for me is solved, but maybe it’s something with programming?

Had GTX 480 (CUDA 2.0), now I have GTX 660 (CUDA 3.0).

Spatial slits aren’t multithreaded. Not worth using at all, as I haven’t found a single test scene where they speed up renders by any appreciable amount, and definitely not enough to offset the build time.

I guess you’re right. I was always thinking it’s maybe giving minor boost, but -1 second here -1 second there and I save some time from that rendering process. :smiley:

So in short. Turning off Spatial Splits was a solution for this problem…
How do I close solved thread? xD