Because FSX performance is strongly limited by CPU Horsepower and I

I dont think 3DMark will be the best indicator for FSX, but in any case, just for shhts and giggles, I did a 3DMark05 run for you at 3.5GHz OC and scored 3D 16745 and CPU 10133.What you really need to do is run my FSX dynamic benchmark, which isn't so video card affected, and see how you go there. PM me for the files.Gary

I literally just did this upgrade - from a Pentium D940 to an E6600. Because my RAM isn't great I haven't been able to OC as much as I'd like, and as much as I'd otherwise be able to, but - performance is much better than it was before. I've been able to turn on autogen and traffic - and leave them on without things slowing to a crawl. For me, the upgrade was worthwhile.As far as what processor to buy - of the three you listed, I would get the 6750 if your mobo supports it - mine unfortunately doesn't, so I had to go with the 6600. I don't think the benefit from the two additional cores in the Q6600 outweighs the lower clock speed of each individual core - because FS can only really take fullest advantage of two cores, and only uses the additional ones marginally, it's better to have two really really fast cores than four that are just 'fast'.But I'm no expert.Good luck with the upgrade.Best,Matt SmithC2D E6600 @ 2.9 GhzArctic Cooling Freezer 7 Pro2 GB G.skill DDR2 RAMEVGA nVidia GeForce 8800GTS 320MB

OK, Thanks, both of you... I have made my choice based also on your CPU result with a E6400 at 10133 compare to my 940D and go for the E6750. Happy landings...

Just for your information,Today my E6750 arrived and because of my little budget I decided to buy a value board which is the Asrock ConroeXfire eSATA2 because I wanted to use my old DDR2 533 RAM and it have 1394 on board etc.First of all there seems to be a bios problem because I can't go higher then 2,4 Ghz. (8x300) When using the auto mode he is going to 100 (x8) so brings me back to the P3 age with 800Mhz.Running CPU-Z is telling me that the multiplier is not 8 but 6 so 6x 300= 1,8Ghz (???) The CPU description is right in the bios startup because he is seeing the CPU as a 6750However I have done the 3Dmark again and is giving me only little bit more performance then my old D940.GPU=6140CPU=8933 Ok, it's a bit higher but not what I expected even on 2,4 Ghz with a E6750

Dear Matt, can you do a 3Dmark benchmark for me with your E6600 on default speed at 2,4Ghz.Thanks...

Are you sure that board supports the E6750 with the 1333mhz FSB?

They sell it with E6xxx compatible. The Bios see it as a E6750 but handling wrong. I have post it already by the Asrock supportdesk.Keep you informed....