Windows 7 What happens if I have 2 video drivers installed ?

If you can't notice a difference or problem in performance, don't worry about whether some test might show some numerical difference. I don't know the answer for sure, but it seems that two drivers would either fight each other, in which case you would see a problem, or it is sorted out by the OS (one will get priority), in which case you would probably never notice. In general, it's probably not a good idea to purposely install competing drivers, especially over something like sleep vs. hibernation. Since you're talking about a card, I assume that this is a desktop. Many people disable sleep and hibernation on desktops because it is very problem prone, there is no battery life to preserve, and it does nothing to save the planet.

There is a kind of controversy between at least NVIDIA and Windows. I have a NVIDIA GTX 560 Ti card and, to be honest, I've never really found out who actually controls my screen etc. I can access controls via Windows, but also through NVIDIA Control Panel. I use NVIDIA.

Like Fixer and patcooke write, if there should be a collision, you would notice it. Main thing would be, if you use controls, use the same one, and through the same command way as earlier.

To look for your computer's performance, use test programs, the basic being http://windows.microsoft.com/en-us/...ex#What-is-windows-experience-index=windows-7

But if everything rolls fine, just drive on!