The pci running at 4x doesn't help, but upgrading that mobo to x16 isn't going to give you very much improvememnt.
Getting a Quadcore CPU will.
I'm affraid your computer is in a trap, i.e. one thing affects the other.
If you do get a Quad core, then your proabably wanting to get a decent motherboard, also at least 800mhz ram, and possibly eventually going to 8800 or 9800 for the Graphics card. Im not sure how much a difference going from 8600 to 8800 will give. I do know that the graphics cards dont give a big difference with FSX as they do with other games.
There are so many people who upgrade just their Graphics card for fsx with not much difference in FPS.
ok well i'll be on the search for a nice quadcore somtime in the near future.. and prolly a mobo..
I bought the mobo because it was very compatable for the time, I could still use my old DDR-266 ram I had at the time, and it had a AGP slot for the 5700 that I had..
a year after getting the mobo, I finally got ddr2, and a 8600..
The videocard is definaly staying for a while... Just got it a few months ago, and already half fried it, and my SATA hdd.. from trying to increase the bus speed..(lol it runs glitchy somtimes, but doesnt affect overall peformance)
also how can I get FSX to utilize the full processor? ive found that it only uses maybe 70-80% of its true power.. ::)
but im sure i can get more out of the current system then 8-10 fps.. ive tried adjusting ingame settings, and the actual driver settings, and using Nhancer, and it all leads to the same 8-10 fps..
while over in FS9, I can run full settings, 16x antrostropic, 16x anti-alising and still maintain 40-50fps. grr I used to like computers.. but lately they've been getting confusing