Graphic card crash? Render Crash? Lighting Issue? I need help!

ArchinaRz

So the problem that I encountered is somehow vague. The case is, I loaded 1 G8F figure and 1 G8.1F figure into the scene, a couple of spotlights, and environmental stuff. The usual rendering time for the scene is about 20-25 minutes at most, however, when i accomplished 1 render, adjusted the figure's pose a little bit, it may take me 2 hours or 3 hours to do the next render with same load of models & figures. But when I reboot the software itself or I reboot the whole system (my computer) the render time would go back to normal, rebooting is a kind of method to solve it, but it's still troublesome, and I also want to figure out the main reason that causes this extra rendering time. Is it the graphic card crashed? Or the render crashed? There is no bluescreening on my computer by the way, everything is working fine, just the rendering time became so much longer once I did 1 render. I reboot the computer manually.

RL_Media

From 20 minutes to 2-3 hours. Sounds as if it is rendering with CPU instead of GPU on the second render.

ArchinaRz

RL_Media said:

From 20 minutes to 2-3 hours. Sounds as if it is rendering with CPU instead of GPU on the second render.

Exactly, and I want to find the reason causing the GPU failure or malfunctioning, btw I turned off rendering with CPU in render settings. 

RL_Media

Most common reason that happens for me, is I forgot to close out the previous render and give it about a minute to make sure nothing is still lingering in the VRAM. If the render window is open, it still has everything stored in VRAM, in case you want to hit that resume button. It's a lot rarer for me than it used to be, but sometimes it would just drop to CPU for no reason I could fathom, and would force me to save, close, wait for the process to finish, then reopen and try again.