Maximum PC

I just got a new case that has 1x 120mm fan in it. I have a couple of extra 80mm fans laying around, so is it better to have more air coming in or going out?

80mm in with 120mm out

or

120mm in with 80mm out

Thanks.

Oh, I know it would be better to buy another 120mm fan, but I need to stop buying for a bit or my wife will have my head. LOL

There's no set rule about cooling and whether in or out is better or worse as a blanket statement. If there's a lot of restrictions, the air could just hang out and warm up before moving on to other parts of the case. Blowing in too much could also just have it leak out of the nooks and crannies without passing over a single piece of hardware. With just 4 screws each, it's best to try it on your individual build both ways to find out.