I'm running on q6600, 4gb ram, 98gtx+, xfi. Vista 64. Runs Fine never drops below 2
Sim speed goes -10 to +10 0 being REALTIME. +1 or +2 means cpu can handle sim computations at double or smth ... sorry the scale isnt exactly clear here. if your sim speed is 0+ the game should run FINE .. at least the sim speed.
Now supcom engine is NOTORIOUS for CPU usage - its just the way it works. It has very good physics but that comes at a price. It can spawn up to 17 treads or smthn, but only 2 threads - Sim and graphics are the main cpu users, next come lan and sound with negligible cpu usage (if working properly) and others are not worth mentioning.
There were 2 problems with supcom: first is bugy sound drivers (try /nosound atribute)
the other is that (usually on XP) threads are being jungled around betwean cores (especialy pronounced on quads) witch has a negative efect on performance.
if you see this in task manger performance charts ... 1 CPu at 100% after a then the load jumsp to second then the third and so on .. you need to update windows and if that doesnt help there is Core maximizer (or optimizer) program flying around in supcom forum (sorry no link).
But anyway seriuosly ppl .. P4 is OLD and SLOW. Sure in a perfect world min requirements would meen that it runs fine on them (and there are some games that do), but its NOT a perfect world ad the fact is mostly min requirements measn the game only starts up .. if you dont like deeling with it there are always consoles.