Most definitely. Make use of that system RAM. It speeds things up by already having the textures loaded into memory, and all it has to do is load from system RAM to the video RAM. RAM is alot faster than your HD.
Make sure AF is either off or set to Application control. AA should be no more than 4x, (preferably, if you are trying to get more fps, turn it to application control. You can always kick it up a notch later if your fps improves dramatically). Make sure Vsync is on. Make sure your monitor refresh rate is set as high as it will go for whatever resolution you are running (example, mine is set at 1024x768 resolution, 85 Hz refresh rate). Your ingame sliders to control video settings move to performance.
Once you see how high your fps will go this way, you can start pushing up the graphics on the ingame sliders until your fps is where you want it. I notice a big difference by keeping the detail range down to just above halfway. My framerates are liveable with it higher, but can sometimes dip down too low. So I learn to live with the lesser setting.
Also, which max texture setting are you using in AH? 1024? 512? 256?