I just finished building a system, but now im getting alot of noise from one of the back end of case fans,I even tried a different fan and it just sounds like its spinning way to fast but lots of noise,I have the fans plugged straight to the powersupply,not sure if that makes a difference, the fans i have, have the bigger power plugs on them also, im on a M2N-SLI ASUS motherboard,and a 500W OZC powersupply, + these fans are cheap types,and both the fans are connected to same power cord on psu,the bottom one is just fine no noise,less air but no noise. what can the problem be? Oh and when i tap the fan while its running it seems to lower the noise for a few min.
There's the noise the fan motor/bearing make, the noise the blades make, the noise from the amount of air moved, and the noise from what the air moves through.
There's also the noise from vibration, which may be one of your fan's problems. Check to see that it is tightly secured to the case. Alternatively, your fan may have a bad bearing that gets its "bearings" for a while when you smack it.
Plugging your fans directly into the PSU will make them run 2-3 times the speed they should, or need too, and make them very loud indeed. I just this weekend finally bought an extension so I could plug the front case fan on my system on to the board, and unplug it from the PSU. It used to sound like an airplane, now it is whisper quiet. Now, on most boards you also can regulate the fan speed relevant to case temperture, so it will only run as fast as it needs to run to keep the inside of the case within a desired temperature range.
You can buy these extensions for about $2 each if you are plugging into the PSU because you cannot reach the case fan plugs on the board, as was my situation.
Well this morning I turned on system and all is quiet fan is making no noise weird,my motherboard has Power fan and a chassis fan plugs atm I have a front intake fan plugged to the Chassis plug on mobo, it runs fine I have nothing plugged to the Power Fan plug on mobo but want to add another front intake fan,so that I have more airflow from front to back exhaust fans also I have the Thermaltake blackWidow V1 fan/heatsink with airflow/exhaust towards the back of tower, temps are at 29-35 c, Im not sure on what temps are normal or to high on for the processor Im using the PC Probe II program that came with the mobo to check temps,is there a better program to check temps in system.
When you've got, say, CoreTemp running - let us know what your idle temps are on each core. You can also use Prime95 (run on all threads, check the option "Detect Rounding Errors") to stress test your cpu. Run it for at least an hour; HOWEVER, watch the temps closely, and if you get cores into the 70C-75C range, stop the test and report back with your system specs including case make/model.