Hello.
After countless hours of reading this site and forum I recently built a new system. I'm very happy with the results since it's inaudible unless I put my ear right next to it, and it's located under my desk. I'm just a bit worried about the temperatures since I don't know what's safe and what's not, if it can it affect the lifespan of components, etc.

I built it in an Antec P182 with a Asus P5K mainboard and Corsair 520W power supply (520HXEU).
Intel Core 2 Duo E6750 (Scythe Ninja PLUS Rev B with a Nexus Real Silent 120mm fan)
Sapphire Radeon X1950Pro (with stock fan, going to replace it with a Zalman VF900-CU wich i bought a while back unfortunately, otherwise I would've bought the VF1000)
Samsung HD501LJ 500GB 7200rpm

I got one Nexus Real Silent fan at the front blowing in, hdd cage removed. Another one at the back blowing out. The top has been sealed. I got no fans in the lower chamber except the one in the power supply.

Hdd temp is stable at 38-39 degrees C, from what I understand that isn't bad and also it hasn't been effected when temps in the upper chamber has risen so I don't think I need a fan there. I got no readings on the power supply but it seems to be running cool and quiet.

Now the thing I've experimented a bit with is the fan speed of the two case fans and the cpu fan. At default they ran at 1150 rpm, wich was fine but I could still hear them when I went too sleep, my computer is located in my bedroom and it's not an option to move it since I live in a small apartment. I turned on Asus Q-Fan in the BIOS and set the case fans to run at 60%, or at 750~ rpm. I connected a Zalman Fanmate 2 too the CPU fan and I have it currently also running at around 750 rpm.

When I did this the temperatures rose (this is at idle in celsius):
ambient case temp: 38-39 -> 46-47
cpu (core0, core1 avg temps): 31-32 -> 37-38
gpu: 48-49 -> 57-58

I use ATI Tray Tools to control the fan speed on the graphics card. So if it goes above 60 degrees C the fan ramps up a bit but it never does unless i play games and when I do that sound doesn't bother me. I've used the same settings both when I ran the other fans at 1150rpm and at 750rpm. Most noticeable change in GPU idle temperature was when I slowed down the CPU fan. If CPU temp reaches 43 C the case fans goes up a bit in rpm and I can always control the CPU fan via the Fanmate, plus that I mostly used the computer for the web, audio applications and watching movies.

I hope I didn't give too much unecessary information, I just want to know if my idle temperatures should be lower. Especially the case and gpu temps seems a bit high. If I missed something or you have any questions go ahead and ask. Any input is appriciated.

Personally the only idle temperature I'd be worried about is your ambient, but I suspect that value is wrong, it would be a very unusual situation where the air heated the CPU rather than the other way around (not saying it can't happen mind you).

Besides idle temperatures are more of a symptom than anything else, I would recommend stressing the system with something like CPU burn and then posting those here.

Thanks for your reply. I actually think I accidently confused the ambient case temp with something else, because I got it from ATI Tray Tools "Enviroment" reading, anyway in ASUS Probe, Aida32 etc I can read the motherboard sensor temperature.
I ran CPU Burn-in, i put it on 30 minutes and got the following temperatures:
CPU temp varying between 52 and 55 degrees,
Motherboard sensor showing 42 C
GPU at 56 C and enviroment, whatever that is, at 47 C

I tried running CPU Burn-in again but this time also with graphics bench software at the same time,
CPU 59-61 C
GPU 69-70 C (enviroment 51 C)
Motherboard 43 C

Do you think any of these temps can be harmfull or are they alright?

Well i am no expert but they really seems alright. My laptop CPU can go far hotter (80~90C) when doing hard compilation, and i've been doing that for 4 years now alost every day for 4/5 hours.

The only way you can get into a problem is when your fan or rad gets dirty or dying and the heat just rise until your PC shutdowns .. i guess they don't even fry anymore these days.

Ok thanks, I just played Unreal Tournament 3 for about 25-30minutes and GPU temp didnt rise above 62 C so hopefully I don't have to worry

Now my only problem is that I live in a one room apartment (I'm a "poor" student ) so basicly I have my fridge/freezer in the same room that I sleep in. So how do I go about quieting that?

Perfectly safe idle temps.

There was a thread about fridge/freezer in Off Topic. I'm basically in the same situation as you are. My solution was to ask the landlord to buy me a new fridge.

I think both idle and load temps are fine for long term use.

Overall what do you think of the p5k motherboard? From what I understand you were able to control the speed of the 2 system fans through bios/qfan but no of the cpu, so I guess the cpu fan header can only control pwm fans.

I havn't had any problems with the P5K. Although thankfully I searched some forums before I updated the BIOS. Apparently most people who updated BIOS from Windows using ASUS program had major problems and had to get a new mobo on warranty. I just burned the new BIOS on a CD (doesn't even need to be bootable) and updated it with "EZ Flash 2" from within the BIOS.

Actually you should be able to control the CPU fan trough BIOS/Q-Fan too. I initially had it turned on, but it still ran at 1150 rpm. I assume this is because it's already such a low rpm for a CPU-fan.
edit: the only fan you connect to the motherboard that you can't control with Q-Fan is the one you connect to "PWR_FAN"

Overall I'm happy with this board, suites my needs and I got no complaints really. I've had a much better experience with this board than I've had before with other brands.

Just a small update,
I replaced the stock fan on Radeon X1950Pro with Zalman VF900-CU and the temperature dropped over 10c in idle! Now it idles at 38-40 C, wich also made other temps, cpu, chassi etc drop a couple degrees.