I have access to either a Pentium 4 3.0 Ghz HT 631 2MB L2 Cache or a Pentium D dual core 2.8 Ghz 915 2MB L2 Cache x 2. I have tested both and it looks the same to me, being the Pentium D a bit slower, due to the slower clock speed I presume, and the fact I was not using a dual core enabled software.I have made some research and it appears the Dual Core CPU handles overclocking very well, so I could be able to ramp up the speed to achieve 3 Ghz with ease. My case is well ventilated and I have installed a third party CPU fan/heatsink that keeps the CPU well under 40 deg. celcius, so I believe I can do it with not much trouble.My question is what can I expect with FSX related to dual core CPUs, or you think is a better idea to keep the P4?Thanks for your help

I would use the dual-core one. But either one I feel like you won't be hurt too badly. But really, I would wait until FSX is actually out, and we start seeing other people's real-world performance reports before I did anything.In my mind, that's the only true way we can really get a handle on what FSX likes and doesn't like.RhettAMD 3700+ powered by Gerbil wheel + gerbil, eVGA 7800GT 256, ASUS A8N-E, PC Power 510 SLI, 2 gigs Corsair TWINX, blah blah, etc. etc.

I'm afraid I can't wait that long. I have the 2 CPUs right here and I must give away to a client PC one of them. He doesn't care which one is it, since it would be for a web server PC, but I would like to get what it should be better for the future.

Take the Dual core.Gary