Would my CPU upgrade from AMD Phenom II X4 965 to AMD Phenom II X6 1100T make a huge difference? Any other ideas?

Amd Phenom Ii X4 965 Specs

Simple answer is no, found out the amd phenom ll x6 1100t is not real good for gaming the best of the phenom ll series is what you have since some of the nvidia gtx 700 series is dropping in price the gtx 760 is a good choice look into that or the amd r9 270x in which stays well within your budget, since gaming is getting more and more call for high end systems might look later on into the amd fx series and a good amd chipset 990fx mobo and soon amd will release the r 300 series as well as nvidia pushing release of more gtx 900 series , right now upgrading the gpu is the best choice another to look at is one step higher a amd hd 6970 , reminder most of these 3.0 gpu is backwards compatible with 2.0 pci-e slot mobos just might experince a small reduce in clock speeds

Check your motherboard specs. If it will support an FX-series processor that would be better.

For graphics you should upgrade to the Radeon R9 270 or 270X and then sell your 6950. Those two cards provide more bang for the buck than their competitors. I didn't see a price/performance check for the R9 280 someone mentioned above.

The gpu is more important than the cpu when it comes to gaming, so if you aren't getting the performance you need, you should upgrade the gpu firxt.

It might actually even be a bit slower in games since the 1100T is a 3.3 GHz. The X6 is only really faster if all cores are being used, and most games will not use use all six.

You're better off trying to overclock your 965 if not go for a full motherboard and CPU replacement.

Under $200 your upgrade options for GPU are pretty limited. For $200 you can get an R9 280 which is basically your best bet. http://www.newegg.com/Product/Product.aspx?Item=N8...

The R9 280 is basically an HD 7950.

Here is the list of supported processors: http://www.asus.com/Motherboards/M4A88TDV_EVOUSB3/... The AMD Phenom II X6 1100T is supported.

The AMD Phenom II X6 1100T will not make a "huge" difference. Little to none at all.

Yes, you can upgrade your pc from AMD Phenom iix4 965 to AMD Phenom iix6. You've to change Mother board and Processor...

If you are doing multi-threaded apps, then yes. Single threaded should be the same.