i7 920 o/c'd to 3.0ghz.
12g DDR3-1333 RAM
2x ATI 4850 1g in Crossfire
2t hard drive
This system should be blowing out frames in the hundreds with every setting on max and yet I am only getting between 20-30. FSX has always been a tough game to max out especially in multiplayer because of all the calculations that need to be made. But the CPU is running much less than 30% most of the time and yet I am still not getting the FPS I expected. Any thoughts?
P.S. For those considering the 4850 in cross fire, I suggest you get the ICE Q version with the vented exhaust. I had the Saphire Radeons in there and the top card fan was actually pulling heat off the bottom card. The PCIe were so close to each other, I could not seporate the two cards. The third PCIe was too low (too far apart from the first) that I could not put the second one down a notch. The cross fire connections were too short. The top card ran at 91°c (yeah, I could boil water on it very nearly). With the Ice Q, I am running both cards at around 61°. Much more stable performance.
To OP, I play FSX with a 8800GTS (g92) 512 GPU OC'd. That was the best GPU to play this sim with but the 9800GTX+ would probably play it as well too.
This game isn't as dependent on the GPU as it is on the CPU. The more cores and the higher the clock the better. It seems to like Intel quads and nVida GPUs best. I tried AMD and ATI as well. It also does not like SLI or Crossfie.
My specs are CPU............Q9550 currently at 3.6Ghz but have played this game clocked at 4.1Ghz. I could max out ALL settings and average mid 30s FPS any where.
I would recommend you get a 9800GTX+ and OC it. With your CPU at 4.2Ghz you should see some real improvements in frame rates. Good luck.