I recently upgraded from an old Nvidia GTX 9800+ to a GTX 560 TI 448. However, I'm getting much lower framerates than I'd expected based on benchmarks run by other 560 TI 448 owners. Specifically, in Battlefield 3, I can run Ultra on 30-40 FPS at 1600x900, but that's not the main issue. On low settings, at the same resolution, I'm getting framerate dips into the mid-low 30s and even in the 20's occasionally. I've got the card currently clocked at 931 Core/2155 Memory and voltage at 1.150. I'm guessing that it's not the GPU causing me to get huge framerate spikes on minimum settings. My system is fairly old, but it meets recommended settings. I've listed the major parts below:
I'm going to have to go with the CPU. Try checking it even, by going out of the game and into the task manager, and see if the CPU usage is around 100%.
You should try and overclock your CPU as said above.
and i will also jump on the cpu band wagon. the cpu needs to be at 2.6 minimum to cope with that gfx card. on single and dual threaded apps. you may also want to increase the fsb slightly to help cope with the extra bandwidth.
although intel cpu's do hand higher spec gfx cards better on low threading apps there is still a limit on how much they can handle without choking. the 560ti is right at the limit. being roughly x2 the strength of a 9800gtx so even though your pushing the limit of what your system can do. its still good for a while yet. that cpu can push 3.3ghz with good cooling and 3.6 with excellent cooling. but 2.8-3.0 will be enough to give you the performance required to ease the strain the gpu is putting on it.
also if you can 1s you know your cpu is stable. either bump the ram speed if its quality branded ddr2 it should be able to handle another 90mhz if it wont then try dropping the timings... if its 5-5-5-15 or there abouts try dropping it to 5-4-4-15 and if its stable go for the boost and drop it to 4-4-4-12 or 13 this will give a good 7-10% more throughput depending on the speed your running at... lowering latency on older ram has much more of an effect then dropping it on newer ddr3 so it is worth trying.