I recently upgraded to Blender 2.79 and since then my dual graphics cards have not been working.
I do a render with both graphics cards turned on and the render takes double the time of only having one turned on.
It’s baffling me. Any advice on how to debug this problem? I miss my renders only taking 10 minutes, rather than 20!
This happens for both full renders and viewport renders.
Based on what?
Right now we don’t even know your OS, model and brand of your graphics cards, driver versions…
And if using both cards is actually slower than using only one, I don’t think the issue is one card not working correctly. Because in that case the render time wouldn’t change at all - as still only the one card is rendering, right?