I have two customers at the moment who both want to upgrade to better video cards. In both cases the new video cards require more powerful wattage power supplies. I have gotten conflicting responses from different sources. I am looking for first-hand experience on this issue.
Case #1. Dell 4600, his video card does not project the secondary video at the same time as the primary video. He has a Nvidia GeForce FX5200 that came with it. If he upgrades to an ATI Radeon 9600 Pro it requires at least a 300 Watt with the video power connector. Presently he has a 250 watt with no video power connector. Dell says that if he installs a new power supply and a problem occurs where the trouble can be traced back to the new power supply it would void his extended warranty.
Case#2. HP Pavillion 6630 has a 90W power supply and the customer cannot play a certain game. She presently has a Intel 8810 or 20 video card. If she upgrades the new card requires at least 250W. The local tech said he does it routinely and it will not harm. HP said it couldn't handle a larger wattage power supply.