>> -heapsize 256000 and -nojoy -noipx.
heapsize should be 262144, I remind you that 1mB=1024kB... heapsize is kbytes,
it should be half of your total system RAM.
You can also put AF to 8x or 16x without much loss in framerate if you have a 9800 or better. (in fact I've never seen performance drops when compared to noAF)
As you said, leave FSAA off...
oh... I just noticed you got a GF6200, a crap card, even a 9800pro performs better.
Put everything to low, including texture details, and you'll be fine
If you can OC it then do, you'll need it