GPU Won't Overclock

So I've been trying to increase my FPS in Bad Company 2. Right now it ranges from 15-30 on medium settings, dx9, and low shadows, etc. So I tried overclocking my EVGA GTX 260. I downloaded EVGA Precision and it shows the core clock at 300 mhz at idle and when I'm in game, it's at 400 mhz. The stock core clock is around 600 or so and I increased the clock to:
Core Clock:702
Shader Clock:1513
Memory Clock:1383
GPU Temp stays around 50*C in game.

In game the FPS is still the same and the clock won't go above 400 mhz. I did a clean install of the Forceware 197.45 drivers, checked the clock on CPU-Z, reinstalled the drivers, even increased the settings on BFBC2 to max and the core clock won't change. Any ideas?

On a side note, it's weird that no matter what I do in BFBC2, the fps won't go above and average of 22 fps. On max settings and minimum settings but it might just be a CPU bottleneck. Maybe RAM too.

Here's my specs:
CPU: Athlon 64 X2 5000+ Black OC'd to 3.1 ghz
GPU: EVGA GTX 260 - 197.45 drivers
PSU: Antec 650w
RAM: 2gb G.Skill DDR2 800

Maybe try using control-alt-del and watching the cpu load while your gaming to check that cpu bottleneck. Of course, you could just overclock the cpu too.

@nonxcarbonx, the CPU is already overclocked, it's a 5000+ black edition OC'd to 3.1 ghz per core, I actually doubt it's the cpu causing the issues because I've changed the cpu priority of BFBC2 to high while playing and it didn't help at all and there are no background program's running. But the issue is why the GPU only shows 400 mhz core clock in game instead of what I OC'd it to or even the stock clock.

@dtechman, no all other 3d apps are good, BFBC2 is the reason I tried to overclock it because it seems to be the most demanding and it's the first time i've experienced in game lag due to a low fps in a looooong time. I know they didn't do a great job at getting BFBC2 running smoothly on the PC but still, on low settings it should be perfect with my setup.

BTW my GPU usuage maxes out at 50-60% in game. I'll check the CPU usage but I doubt it's 100%.

Am i alone in thinking it might be a Memory bottleneck?

I'm an intel fanboy so i don't know much about the interface between the CPU and Ram In an AMD chipset.

The Low Core clock at idle Is the energy saving function of your GPU and it should pick up as soon as it comes under load...