The fans in your computer may not be able to keep your machine cool when you add higher powered cards. Increased temperature may damage your computer components. One solution is to add another cooling fan to your system, rather than try to upgrade what you already have. You can attach inexpensive ($10.00 – $20.00 range) exhaust fans to any open ISA or PCI slot in the PC case. The quiet, reliable little fan sucks all the hot air out of the box and blows it through the slot vent. The fans are powered by a standard connection to your computer’s power supply harness. A search for Expansion Slot Fan displays hundreds of sources for this type of device.