No, I don't get such a message, the ram memory is using 80% and it doesn't give a warning. My problem is very complex. i try the scene on another pc, no problem, but i see a problem on my computer. Can materials and objects cause these problems? I tried corona benchmark and now I can't see any question in this. but as I said, while rendering in the first place, my cpu frequency was increasing and decreasing only in the pass transitions, then my cpu frequency was low in denoising mode.