GPU+CPU rendering , but using 2 different tile sizes for optimal speed for both?
I know Blender has added a gpu+ cpu for the newer builds , but it uses one tile size which is not effective for both types of hardware. For example my 1080 ti needs an optimal tile size of 426, but my ryzen 1700 needs a tile size of 8x8. So choosing one size for both doesn’t make sense since they’re very different.
Unless I’m wrong...please correct me.
6 Comments
In recent builds, the tile size doesn't affect GPU speed that much anymore. For example on my setup in Blender 2.8 alpha only on GPU, the BMW Benchmark (128 samples) renders in 42 sec on 256x tiles and in 44sec on 32x tiles (which is in my experience the best tile size for combined rendering). CPU + GPU renders in 36sec.
A thing that slows down rendering on small tiles is Denoising - but I think they are already discussing to use a different tile size for denoising or optimize it better.
Anyway combined rendering seems to be in a very early state. You won't see huge improvements in rendertimes unless the scene is very complex.
@Simon Storl-Schulke: To compare: In good old Blender 2.79b, a tilesize of 256x rendered in 1:01min (cycles really got a nice performance boost in newer builds) and ca. 8min (i stopped it after a while because it took ages) on 32x32 tiles.
It not that it doesn't matter.
It's that it has been worked so that the GPU can have an almost equal render time at a certain low tile size compared to their usual big tile size. The tile sizes depend to one rig to another and usually the small tile isn't as fast, but combined with the CPU it begins to get interesting (but watch your PSU heat tho, especially if you have an entry level one).
@Simon Storl-Schulke: Really? Didn't know that. Guess I don't need the "auto tile size" addon anymore...
@Simon Storl-Schulke: Very interesting, So I guess my problem is solved, if the tile size does not matter then I guess we are catering to the CPU.
@Lopo Isaac: Keep the auto tile size addon, he will still adapt the tile's ratio to your render ratio. The only thing that will change is that you will have to select the aimed "magnitude" (if that word make sense).