I am thinking about upgrading my computer, I get a decent framerate in Rift right now when not in invasions or closing rifts where it goes down from around 35fps averade to 15fps when there is a lot going on.

So while I am content with the usual 35fps I would like to improve my computer to have at least 25fps+ during invasions etc. without having to lower the graphics quality.

I have a core i7 920 cpu, 12GB ram and a Nvidia Geforce GTX295 graphics card, so my upgrade paths are a bit limited. I am wondering if upgrading my cpu from a 920 to a i7 960 would improve the fps? Or is my only option to upgrade to a Geforce GTX580 graphics card?

Because while the 295 doesn't support DX11 it does compare in raw performance with most current graphics cards or is only a few fps below them, as far as I can see.

Is there anything else I could buy that would improve my fps?