I have a Quicksilver G4 that I assembled from Parts bought on the web. The last part I want to put in - a dual 1 Ghz card - causes problems. (Memory is maxxed out at 1.5 Ghz, it has a 9800 ATI card in it, runs 10.4.11) The major problem is that it overheats and shuts itself off after a while, leading me to think it's a heat-related issue. However, after numerous times cleaning, swapping in and out parts, etc, nothing seems to stop this. Is there any way to fix this? The card was part of another Mac system and made by Apple, in case you were wondering. Thanks.