Slow computer after new card installation

What is your motherboard?

ASUS P8Z68-V PRO

nobody?

Is heat an issue? Maybe get something to check the temperatures of your computer.

Sorry about the delay. I asked about the motherboard because I heard a lot of issues with 670. In one forum I read that it is due to incompatibility of the 670 to PCIe 3.0 slots but seeing that you have PCIe 2.0, that does not come in to play.

A lot of other 670 complaints is the "Driver crashed but has recovered" but there is also no definitive fix on this. One of those who have PCIe 3.0 claim he fixed the problem by setting the BIOS to PCIe 2.0 ( but others complained that they purposely bought PCIe 3.0 feature & its a waste of money if they just have to revert back to PCIe 2.0 ).

Many of the people who complained about problem with 670 said that they have already tried all possible remedy like reinstalling graphics cards, monitor temperature & doing stress test but found to reason. Some try to put the graphics cards in another slot ( if available ).

You can see a lot of these issues in forums by googling :"nvidia 670 problem"
Here is one:
http://tech.pnosker.com/2012/05/21/nvidia-potentially-r...

Sorry if I can not be of much help. I do not have the 670 myself but hearing a lot of problem here, I do not see myself purchasing one any time soon.

I believe it's a driver problem, couldn't really see anything else. Of course, it could be bad card, but a bad card behaving like this is chance one in the million. Probably drivers. I'd suggest you to reinstall Nvidia drivers first. Secondly, if you have a free partition (at least 30 GB), why don't you try installing windows to it and see whether the problem go away?

If you've ever had a memory leak issue, then you know what I mean by it feels like something is draining all your resources and your computing power drops down to the speed of a wrist watch.