The brush performance varies not as expected if compare color deeps This result from the same hardware with different os system with and without opengl on: Nvidia GTX660 Win7 64bit color deep: 8bit slower than 32bit (unexpected) Linux Mint 14 color deep: 32bit slower than 8bit (expected) Reproducible: Always There is a bug or restriction that drops performance for nvidia cards with 8bit color deep or maybe nvidia is much more faster with 32bit or their drivers are buggy. This info is perhaps useful for other users or a dev get an idea what is going on there.
Created attachment 91462 [details] Performance analyse records Here is a compare for a played macro in 8bit and 32bit, maybe it helps. Recorded with AMDs CodeXL.
This is expected. Nvidea card are optimised for floating point values, and you will find they're even faster on 16bit float images! Issue though with these sizes is that they do eat ram. I'll leave this open for now, for the others devs to take a look.
Well, thanks for the info. But i wonder why the different bit modes seems to use different dll calls and counts.
I'm sorry, I know it's observed behavior, and it would be better if it wouldn't happen, but we cannot influence the performance characteristics of display drivers....