IMHO any one who recommends a full reinstall of the OS to fix an issue ( especially hardware ), has no clue what they are doing.

Would you replace your motherboard with a different model, without reinstalling Windows? I wouldn't.

Video cards are a little less intrinsic than a motherboard, but they seem to share a certain degree of "breaks if you look at it wrong", and reinstalling the OS can't actually hurt.

[quote name='Shippou' timestamp='1349998039' post='4989305']
IMHO any one who recommends a full reinstall of the OS to fix an issue ( especially hardware ), has no clue what they are doing.

Would you replace your motherboard with a different model, without reinstalling Windows? I wouldn't.

Video cards are a little less intrinsic than a motherboard, but they seem to share a certain degree of "breaks if you look at it wrong", and reinstalling the OS can't actually hurt.
[/quote]

I think it's a software issue, because before formatting it worked like a charm when I updated the drivers but after some random hours it started acting slow again. Everytime I installed new drivers it worked perfectly, can't be a coincidence...

Now that I've formatted and installed everything again, we'll see what happens...

I'll start with Borderlands 1..
Before: around 30 fps with max settings
Now: +70 fps (or more, cant really tell because it runs so smooth) with max settings

The problem was software related, after formatting and re-installing everything the videocard performance issue was fixed. So I guess some hidden ATI files were conflicting with the Nvidia drivers.

Thanks to all for the help and tips!

Just FYI, if you don't want to go the reinstallation root in the future, Driver Sweeper can be a life saver.