My brother has a HP Pavilion A6257C. He wants to get a video card like either a 7900 or 8600 for it. What all does he need to do to get this working? Reading the manual online...it says:
An add-in card is a circuit board, such as a PCI or an AGP card, that fits into a PC add-in
card slot. Your PC contains several add-in card slots that can be used to add components
to your PC. The PC component configurations vary by model.
WARNING: Do not overload the system by installing add-in cards that draw
excessive current. The system is designed to provide two amps (average) of
+5 Vv power for each board/card in the computer. The total +5 Vv current
draw in a fully loaded system (one with all add-in card slots filled) must not
exceed the total number of slots multiplied by two amps.
NOTE: A power supply upgrade may be required for certain graphics card upgrades.
Check with the graphics card supplier for more information about power supply
Will I face any Vv issues? Will the 300 Watt PSU handle any of these video cards?
I think he should get an HD 3850 512MB. It's about twice as fast as the 8600GT in some benchmarks. An 8800GT would be even better - if it can physically fit in the case. You can replace the PSU with something cheap but still good, like OCZ StealthXStream 600W.
Pre-built pc's usually come with a generic PSU that is good enough only to power the installed parts. On your PSU there should be an information sticker that says how many watts and amps are available for various voltages. In particular, the 12v rails provide power to the vga cards, and the amps supplied there is most important. Post that information if you can find it. Read this link for info on how much each type of card takes. http://www.atomicmpc.com.au/forums.asp?s=2&c=7&t=9354