I did that about a year ago, upped my RAM to over 4 GB,, installed an Extra Cooling Fan,, and got a way better Graphics card,,,
QuadCore Processor,,,,,
*** Also had to AMP up my POWER SUPPLY to a 650 Watt - very IMPORANT when choosing a Video card that the Video Card matches your power supply requirements - READ the Requirements on the side of the Box of the Video Card - Don't Trust some Sales guru, they'll tell ya anything,, good thing I checked at the time 1st !!!!
I used to be a NVidea fan,, but, I thought I'd try something different,, and I Opted for the XFX series Graphics card at the time,,, the XFX 6850 Graphics card,,,
I have yet to have any problems, after setting it up, and it seem to me to Render the Clouds, Water and Sky better than N Video, and without all the constant tweaking and messing around.
I don't use Rex or any other software,, I try to keep it KISS,,, Keep it Simple Stupid !
Get to many other programs running in the back ground with FSX and all I've heard is problems and complaints on those programs Forum Boards.
Try 1 of those XFX Graphics cards , Quite sure they've come out with a newer better Version than the 6850 series by now, there was a 6950 series out as the newest,, but theres probably a new one than that out by now !
http://xfxforce.com/en-us/home.aspx http://www.youtube.com/watch?v=8xanF38jfho http://www.youtube.com/watch?v=Htj_VpmP39k http://www.youtube.com/watch?v=jYf6gbfCaVs Jetranger