Here are some performance metrics for Battlefield 3. This should help you decide whether or not you feel you need to upgrade or if you're in the market for a new product, this should help you determine what kind of performance you can expect. Using Fraps, I was able to pinpoint min, max, and avg frames per second in various configuration. Most of the tests were done on stock speeds for both the CPU and GPU on Low, Medium, High, and Ultra default presets provided within the game at 1920x1080 resolution unless specified otherwise.
Game/Level: Battlefield 3; Operation Swordbreaker. Every test was conducted as close to same scenarios as possible.
The platform was on a Rampage III Formula, and Intel 980x CPU. The CPU was overclocked to 4Ghz in some of the tests but the stock frequency is 3.33Ghz.
I also got metrics on G74Sx-A1 with a GTX560TI m and Intel 2630QM CPU.
The following metrics show a comparison between GPU performance with different presets. 
You can click on the graph below to get a comparison based on GPU performance in Preset categories.
You can also see from the screenshot below it uses about 25% of your CPU resources.
Screenshot proof:Mars II/Rampage III Formula/980X: Mars II is simply incredible for a single card. With stock clocks, it produced almost double the frame rates as a single Matrix GTX580.
High

Ultra
Matrix GTX580 Platinum/Rampage III Formula/980X: The GPU's stock clock is set at 810Mhz and was overclocked to 910Mhz. I recommend overclocking to at least 910Mhz to have incredible game play in ultra presets.
High

High GPU OC 910Mhz

Ultra

Ultra GPU OC 910Mhz
GTX480/Rampage III Formula/980X: I needed to drop the presets to high to get about 60FPS, still a very strong card.
High

Ultra
GTX560Ti DirectCU II/Rampage III Formula/980X: This card does quite well in Medium presets and has amazing SLI scaling performance which offered double the frame rates. I can easily play in ultra when in SLI. When overclocking the cards by 130Mhz, i saw a 3FPS increase. in SLI i overclocked each card by 110Mhz and saw a 6FPS increase. When overclocking the CPU i didn't see any performance increases in Ultra presets because it was heavily dependant on the GPU, but in medium presets i saw a 2FPS increase since its less dependant on the GPU and the CPU contributes more.
Medium

Medium GPU OC 960Mhz

Medium CPU OC 4.0GHZ

High

Ultra

Ultra CPU OC 4.0Ghz

Ultra GPU OC 960Mhz

Ultra SLI

Ultra SLI GPU OC 940Mhz
GTX260 TOP/Rampage III Formula/980X: If you have a GTX260, its playable on low settings but honestly who wants to play on low settings.. It just looked like crap...
Low

Ultra
8800GT/Rampage III Formula/980X: If you have a 8800Gt still, its seriously time to upgrade. Low settings and getting 44FPS? I was annoyed.
Low
G74Sx-A1: Note that this is a notebook, so i had to turn down the resolution a bit to increase frame rates but still enjoyable and awesome for notebook performance!
Low

Medium

Medium 1280x720

Medium 1366x768

High 1280x720

Ultra