Hey Karba, I have a new issue with maybe the same type.
After i disabled my Multi GPU mode, i reach 3-4M samp/s at 800x950 pixels res, it's cool.
Yesterday i tried to render at 3000x3500 pixels res with same scene, nothing changed, and the octane viewport appeared " WARNING! RENDER FAIL! " message although rendering is still processing with ~1.8M Samp/s .
And after that when i back to 800x950 pixels res the " WARNING! RENDER FAIL! " message still exist and my speed drop from 3-4M samp/s to ~1.9M samp/s, mem drop from ~0.8/1.6GB to ~0.8/0.8GB
Any idea ?