Hi guys, I just replaced my old celeron D CPU with a pentium D 940.. I just used the orginal intel heat sink (the fan) without any additional cooling equipment(I did remove the old and apply a new layer of heat paste). However, I played PMDG 744 right after I installed the new CPU yesterday, it runs perfect with frame rate up to 25. I left my computer on for 20 hours and then played PMDG again, the frame rate dropped down to 5. I then restarted the computer and look at the CPU temp in the BIOS setup manual and the temp is 74 degree C. Is the CPU temp too high and slowing down my PC performance? If yes, can anyonw suggests a low cost remendies?thanksben

74 is high but not drastically high, of course your motherboard MAY be slowing down the CPU as it detects it getting too hot (SpeedStep) so without more info it would be difficult to tell, but I will say this much. A P4 D940 requires a lot more heat dissipation than a Celeron and we are talking a Prescott core here, so I mean a LOT more heat dissipation. You really should have changed the heat sink, so I would do that regardless, and the 940 requires the mother of all heatsinks being one of the hotter processors Intel has ever made. I use one of these http://www.scan.co.uk/Products/ProductInfo...roductID=369638 and it works a treat, but it may not fit your motherboard. Check with whoever your nearest vendor is.But, as I say, that may not the the real reason for the slowdown. You could have something eating up your memory. Retry the test, but reboot before you play again and see if the frame rate returns to normal. If so then you have something eating memory. As to what, I'll start with the obvious (malware, viruses, trojans, etc. etc.) but I always make sure that I only have the bare minimum as to what is really needed in my Startup Folder and Registry "Run" keys. No "Adobe Quick Start", no control panels for my graphics or sound, or any fancy keyboard managers or anything. If it isn't necessary to system security or functionality then it goes.

74c is too hot. Abit set my default, emergency shutdown temp for my P4 at 80c. High 60s is about as high as you want to go. My initial O/C adventures took me to the high 60s before the system became unstable. Got a thermalright cooler like this: http://www.thermalright.com/a_page/main_product_xp120.htmI got another 300 mhz of stable O/C. I now run at about 58/59C on final over LA with traffic / autogen on max and 8 fps (ie, CPU totally maxed out!) High 50s will keep you off any thermal limit. High 60s starts to thermal limit. Into the 70s? The system will protect itself with blue screens or turn downs. Gotta cool that thing off. This one 'll work too: http://www.tuniq.com.tw/Cooler%20Info/Tower-120.htm

Hi,Thanks you very much... I just found out the reason: the heat sink was not properly fasten to the mother board... Now the CPU temp remains at low 50. Is low 50 a reasonable temp or I need to buy a good heat sink to bring it down to 40?thanksben

Anywhere in the 50s is fine. Until you start O/Cing with liquid nitrogen (at freezing temps), cooler won't matter. You're good to go.

Thanks, so I won't be better off if I buy a better heat sink, will I?thanksben

Not unless you plan to overclock. A good heatsink will keep the CPU in the 40's. Mine maxes at 44 at full burn, but that's just for us nerds ;-)