Do case fans really make a difference? Will they lower the temperature of my cpu and motherboard? If so what type of case fans are the most quite [pci slot ones, big ones, small, hd ones etc] and how many should typicaly be put into a pc?. Thanks

Yes, they will make a difference in terms of CPU and motherboard temps. However, if you open your case side and the CPU/mobo temp does not drop much, say like 1-2C difference compared to case closed, then having more case fans is kinda useless. What I would do is ensure that the cables are wrapped, remove heatsink, clean thermalpaste and add arctic silver 5 and change the stock heatsink to a better ones like Zalman CNPS9500 or Thermaltake CL-P0024 w/ 92mm vantec stealth fan (<21dBA)... But typically, you want 1 intake fan below the power button if there are air vents and 1 exhaust fan below the power supply for optimal air flow... In fact, that's how I set up mine w/ a 8 year old HP case... lol... TMP-Man Asus P5P800-SE P4 506 @ 4100Mhz 1.525v Thermaltake CLP0024 w/ 2000RPM FAN + AS5 1GB Corsair 2-3-3-5 DDR400 40GB 5400RPM/120GB 7200RPM HD Radoen 9500 mod 9700 @ 375/600 CHS+RHS

If you were sitting in a hot room with no circulation, would putting a fan in a window make a difference? What about putting an intake fan in one window & an exhaust fan in a window on the opposite side of the room...would that be better or worse?

If you want to less the cpu temp then try to add much thermalpaste and cover it =D but not too much. AMD X2 3800+ @ 2.4ghz Palit 6600GT 256MB @ 500/1000 ASUS A8N32-SLI Deluxe 2x512MB Corsair PC3200 @ 433Mhz soon 7900GTX 512MB Either ASUS or BFG Thermaltake Tai-Chi with water coolin

yes, actually a fan is the window will make a difference. remember, a fan/heatsink setup can never lower the cpu to less than the temperature of the room that it is in. if it is in a hot room, you will be trying to pass hot air into the case then through the cpu heatsink, which will not do much. the cooler the room, the cooler the case. the cooler the case, the cooler the cpu (this of course only applies to the fan/heatsink setup) a peltier setup can lower the temperature to cooler than the case temp.

"yes, actually a fan is the window will make a difference. remember, a fan/heatsink setup can never lower the cpu to less than the temperature of the room that it is in. if it is in a hot room, you will be trying to pass hot air into the case then through the cpu heatsink, which will not do much. the cooler the room, the cooler the case. the cooler the case, the cooler the cpu (this of course only applies to the fan/heatsink setup) a peltier setup can lower the temperature to cooler than the case temp." Thats why we overclockers like winter :~) Tt Lanfire MSI K8N Diamond 3000+'Venice'@294x9x3 1:1 1GB PC3200/4400 OCZ Powerstream 520w 6600GT WDCaviar 160gb sata x2