I just installed a new cpu fan and heatsink in my AM2 mobo. The idle temp is 45. My question is my sensors and the bios reads the fan speed is 750. On the box it says fan speed 1300 I guess that could be under load. The only reason I noticed this is because the sensor program beeps because it is reading the speed at 750. If my cpu temp is okay do I need to be concerned with the low fan speed?

You may need to reset the 'green' settings on the mobo to make the fan run at full all the time. Do this in the BIOS.

Thank you, if I don't change the settings is this a problem as long as my temps are in range?

Yup - but perhaps install everest.exe from majorgeeks and keep and eye on it for a while.

If your temps are fine when the fan speed is lowered it shouldn't be a problem in the long run. I had an Athlon64 3200+ later replaced by a 3800+ Athlon64 X2 & when the CPU idled the speed was lowered & the CPU fan would actually stop.

The constant on/off switches didn't kill the fan after months of use either.

I have an ASRock Quad core system, with a ZeroTherm Nirvana cooler. When the system is first turned on the fan doesn't spin at all, after a few minutes it starts spinning slowly gradully increasing. The CPU temp never goes above 36C, and the motherboard is set to control the fan speed

You got the AMD quiet fan thingie going. Just go to BIOS hardware fan control blah, and turn it off, You want the fan to be @ 100 percent full speed @ all times. If you want a CPU to have a long life,,,

Thank you, I did have to go to bios and lower the quit fan to 40 co now when it goes above 40 the fan speeds up