using my relatively old X1900XT (waiting for the new 8800GTS to be released in the new year)and I'm quite surprised to be honest how (1) Less blurries(2) Noticeably smoother(3) Less "option" dependant - ie I can now using "high" clouds, bump up the AI traffic, increase autogen etcI was assuming before the game was GPU limited, but although it probably is to some extent (running at 1900x1200) - upgrading the CPU has made a much bigger difference than I was expecting after reading some of the posts on here.E6600 before was running at 3.3 gignew Q6600 (Q0 one) - running at 3.5 gigDidn't want to remove my motherboard to install a "back-plate" style cooler - so kept my old Freezer 7 Pro - and I have to say its doing a much better job than I was expecting.temps for the Q6600 overclocked = 35C idle and about 67C load (Prime95)overall very pleased with the upgrade and can certainly recommend it to othersMark.

Mark,I too noticed the whole feel of my system, not just FSX, is now smoother with quaddage powering the show. I also recycled my Arctic Cooler Freezer 7 Pro, half expecing it to choke with the extra heat (especially at OC speeds with extra volts), but it handles the load very well indeed. In fact, I am flying online with FSX with a handful of addons right now running at 3.5GHz @ 1.4V and my CPU temp (Tc) is hovering around 52C with the CPU fan speed on 1600RPM (out of 2700RPM max).I wouldn't go as far to recommend this upgrade to others already with an OCed C2D, as those systems already run FSX quite optimally (albeit more maxed out), however I am certainly putting the quad as a stronger recommendation than a dual to those who have not already made the jump to C2D.Gary

Did you wipe the hard drive, starting fresh, or did you simply plug the existing into the new quad?RhettAMD 3700+ (@2585 mhz), eVGA 7800GT 256 (Guru3D 93.71), ASUS A8N-E, PC Power 510 SLI, 2gb Corsair XMS 3-3-3-8 (1T), WD 150 gig 10000rpm Raptor, WD 250gig 7200rpm SATA2, Seagate 120gb 5400 rpm external HD, CoolerMaster Praetorian

plugged straight in - since the mobo etc were the same (775 socket)- no need for re-install

That's ok. I just wanted to rule out the possibility that your good results were not half because of a fresh install.RhettAMD 3700+ (@2585 mhz), eVGA 7800GT 256 (Guru3D 93.71), ASUS A8N-E, PC Power 510 SLI, 2gb Corsair XMS 3-3-3-8 (1T), WD 150 gig 10000rpm Raptor, WD 250gig 7200rpm SATA2, Seagate 120gb 5400 rpm external HD, CoolerMaster Praetorian