For about a week or so it was working flawlessly in games, browsing, etc then I bought a VelociRaptor drive and I switched to AHCI mode and reinstalled the system (Win7 64bit). I don't know wheter this was the cause of the errors I'm just writing down the events.
After this I got some crashes (eg. artifacts) in 3d games, especially in BF3 but interestingly not in Skyrim or Batman AC. I got this on regular web browsing as well. It's not a blue screen crash but a temporal one ending with the message something like this: The VGA Kernel driver has stopped responding and successfully recovered
I searched through the net for information but nothing worked for me only for a little time being. I tried tuning the voltages a little bit (RAM and VGA) tuning the VGA speeds down and the RAM speed too. Only temporary solutions. I also tried with different nvidia drivers.
I only ask for advices because I suspect my VGA card faulted and I will return it if I'm right. But if there is any other solution I'd like to try it.
(Also I'm interested in fine tuning my BIOS settings, not overclocking if anyone can help in that
Since then I switched pci-e slots without luck. I dowgraded the GPU clock to 660/1320 That's seems to be stabilised the card. I had no errors. (I had errors when I just raised the GPU voltages form the stock 1.035v to 1.080v and 1.1v)
BUT what is the conclusion. The card is defective or my PSU is? Please help because I would RMA the card.