I'd personally go with the 6970 or 6950. The extra ram could be of use later on when you decide to upgrade your monitor or go with eyefinity. In addition, games like BF3 could use the extra memory.
It's time to upgrade. To da 2700k!
In all seriousness, try running a cpu and gpu benchmark tool like 3dmark vantage and 3dmark11. Then compare your scores with others and see if it's the CPU or GPU or mobo at fault.
Yeah, that's probably not it but who knows! Maybe you just have a defective unit.
I'm scared of buying a U2410 now. This makes me have second thoughts. :(
Here is a comparison chart:
http://www.htomega.com/faq18.html
I myself have the Claro Halo XT and there is quite a noticeable difference between it and onboard audio. I have the Corsair SP2500 though. I got lucky and snagged it up for $50 off CL. It was totally worth my ~2 hour bus ride!
You...
At that resolution and even at 1080P, games should be very playable. I would wait until the 7800 series comes out and compare the performance and price vs getting another 460.