GPU Upgrade...

Wanting to upgrade my GPU, partly cause I don’t think it’s capable of CUDA and I just can’t get it to work with Blender at all, also, I think it’s just time for an upgrade. I’m not a hardware guy, I have no idea what I should be looking for. Right now I have an nVidia Corporation G92 [GeForce 9800 GTX+] (rev a2), my price range is about $300. Any hardware guys out there that can point me in a good direction?

Hello?
Anyone there?

CUDA + 300 USD = GTX570
it is as fast as it gets unless you buy a GTX580. The cheaper alternative is to get a 470 or 480 on ebay, in terms of CUDA they are pretty much as fast as their 500 series sisters, as the DPFP CUDA performance for GeForce cards is capped. If you want energy and temperature efficient: no way around the 500 series - the 400 with reference cooling is loud, hot and they consume more power than the 500 series.

And to clearify, the GTX9800+ is a GTS250 and it´s perfectly capable of CUDA. The problem are the various compute capabilities. You´ll see it as CC. Most apps today use CC 2.0 some bleeding edge stuff already CC 2.1.
2.0 is GF100, GF110 and 2.1 is GF104, GF114 and GF116. (Those are GPU types, NOT GeForce Types)
Your GTS250/GTX9800+ only supports CC 1.0.

On a sidenote, the GTX9800+ is quite fast in Blender viewport and I´d keep it anyways. It should be pretty much as fast in OpenGL solid as the GTX570, just trail it. You can keep the 9800+ for viewport and use the new card for GPGPU raytracing and gaming.