Re: GeForce FX5600 XT Driver prob
There are a whole slew of things that can adversely affect drivers.
DVD - CDroms
other software you have running
Ambient temperature of the room
It all depends on how the system is setup
if its overclocked, if all hardware is working properly
The list goes on and on.
Basically you just need to see what drivers ,bios and settings work best for Your system.
And like saturnotaku said, "Just because drivers support a particular card doesn't mean newer versions will offer performance benefits".