That is what I did. It is blowing at an angle across the motherboard, then the other half of the case is open for the air to get out. It really works great, especially with the cpu fan I have, it blows directly at it. I went from about 48c cpu to 38, and 44 system to 32 system. I have had it this way for about a month, and havnt noticed any dust build up, but I have a can of compressed air that I blow around every once and a while just in case.CrazeD said:Just slapping it against the side blowing straight against the motherboard probally won't help at all, it will just circulate heat if anything. But, if you can get it to blow across the motherboard or blow at an angle, then I don't see why it wouldn't work.