I just won (by accident) two 5830s on Ebay. Unfortunately, my power supply won't support both. I'm ready to start mining, but between an ASUSTeK and an XFX, which is the better of the two? The ASUS is brand new while the XFX is slightly used.

Good idea.

I'll definitely test them both out to make sure they work, but I don't know. It depends on which one I keep I guess. I'll let you know.

I thought about that. Unfortunately though, the ASUS has already been opened. Supposedly he opened it, used it for an hour, and put it back in the box. So in either case, I have two opened boxes (assuming the XFX comes in a box). I might see if someone will let me use it in their machine in exchange for a few Bitcoins a month or something.