Welcome to SPCR!
First thing is to identify the noise makers.
The aim is remove all noise makers and then add back one at a time to see how much noise each adds.
First turn off the PC at wall or back of PSU. Unplug the CPU fan (cable only - leave heatsink on CPU), the hard drive(s) power and the case fan(s). If you have a video card with a fan remove that (the whole card) too.
Then turn the PC on, it wonâ€™t boot as the HDDs disconnected etc. The only noise maker should be the PSU fan(s) This gives you a baseline noise level, if itâ€™s too loud youâ€™ll need a new PSU or swap/slow the fan in the one you have.
Be Quiet! PSU
Donâ€™t leave PC on long (<30 seconds) as CPU fan is off!
Turn off PC and reconnect CPU fan and turn on again. If this adds a lot of noise itâ€™s the CPU cooler / fan you need to look at.
As your motherboard manual makes no mention of fan control (Q-Fan in Asus speak) Iâ€™m guessing it doesnâ€™t have any so youâ€™ll want a fan controller, eg
There is also the Zalman Fanmate.
You may find that your existing CPU cooler is OK with the fan speed slowed down, what CPU / cooler do you currently have?
You can use Speedfan
to report the temperatures and fan speeds of your system to see if you have cooling headroom to reduce noise.
As far as I know s754,s939, AM2/AM2+ all use the same mounting, this is good as gives you lots of choice
Example of fairly cheap CPU heatsink thatâ€™s compact but should perform well is Xilence IceBreaker
Much better but also taller cooler Xigmatek S963
These are both 4pin PWM controlled so you will want a fan controller with them,
You can then power off the PC and connect the HDD(s) and see what noise they add to your system. Repeat with Case fan(s) and, if applicable, the video card.
After all this youâ€™ll hopefully have an idea what needs to be tackled and we can offer further advice.
Good luck, Seb