The problem disappears when the card is removed. I tried the stock drivers again, that came with the CD. Problem still persists. I'm running the latest flash and java, although even when I disable Flash, nothing improves. Another annoying thing is that the onboard intel hd 3000 is completely disabled when I put the card in, so basically I can't use Lucid Virtu and I can't use my motherboard's VGA connector. Is that normal?
Btw I checked that 'speccy' tool, it doesn't get a reading on the GPU, I guess it doesn't have a thermometer.