I just upgraded my video card from a NVIDIA GTX 260 to a EVGA NVIDIA GTX 650 Ti SSC. The problem is that my frame rates are now HALF of what they were on the 260. All my settings are the same and the driver version is also the same (the latest driver version: 314.22).
 
The 650 is PCI 3.0 ready but I believe my motherboard is 2.0. However, the info with the new card says that the 650 is fully compatible with legacy 2.0 components.
 
Any idea why I am getting 50% LOWER frame rate with the new card?
 
*Intel DP43TF Motherboard
**WIN XP 32Bit
 
Aviar

Its not the PCI-E 2.0 hurting the cards performance if its only a single GPU.
 
The difference between PCI-E 2.0 and 3.0 is only noticeable in SLi configs and when running 3 monitor surround.

My 650ti required a lot of tweaking coming from my 260. I was not pleased at all in the beginning and truly regretted my new upgrade. Unless you absolutely have to use it do NOT use the RTSS with Precision X. There seems to be a lot of driver/software conflicts and you will get a ton of video driver crash errors. I stopped using that and problem solved for that issue. You do need that clean install of the new drivers and make sure all old stuff has been wiped. Also, do not save your settings in Precision X and reinstall it. Other than those simple solutions I just went ahead and reinstalled my OS so everything was new and no old stuff lingering. My card is doing better than it did in the beginning. I get a lot more visual enjoyment over my 260, I just HATE the loud fan noise after coming off of a water cooled card.

 
Glad you got it working right. Good job.