i have asus a8n32 sli deluxe and in idle state or under light work, the    temperature goes to 51 deg and while gaming it goes to 53...these temperatures might not be that high, but Asus sets the default mobo temp. in its PC Probe II at 45 deg....
 
also the PC Probe shows my PSU fan at 0 rpms??? ive checked the fan is working fine...in the bios it says NA for the PSU's fan..its started only recently, while it gave me atleast some reading before.

I wish I could help! Instead, I just stumbled across this post, and I have encountered the same thing! mine is around 48 idle, and even that gets a warning from pc probe. I think I'm putting in an extra 120mm fan on the side of my case - more due to the fact that I'm running SLI with 2 x 7800gtx 256 cards, and it gets pretty toast in there

one thing that allways helps is see how the air flow is doing in the case.

I replaced an A8N premium for this A8N32 on saturday and i got the corsair 3500LL ram too thats made for the board, i couldnt fit my thermaltake heatpipe heatsink cause of the size of the ram modules.  
 
The A8N premium used to sit nice at 34 degrees and go up to about 43 under gaming with 2x 7800 GTX sli, the A8N32 sits idle at 42 and goes up to 56 under gaming with SLi. I think its the graphics cards running under 16x pciE rather than 8x pciE thats causeing the high temperatures.  
 
Also earlier i was just web borwsing and the computer just shut off for no reason, strange. cant be psu related, i have the enermax liberty 620watt.
 
Its going to be a hot summer with this thing pumping out 50degrees of heat!

I too have the same problem, 47 degrees C straight out of a boot.  Anyone have any idea what the heck us up with this?
 
Fritz

 
Innacurate sensor, bad probe reading.. if everything is stable, don't worry.

It's not the mobo problem not registering system fan's rpm but is the fan itself. I have several kinds of 120mm fan, but only 2 of the fan can my motherboard detect the rpm. I don't whats' causing this, but the fan that my mobo ( GA-8N SLI Royal) is able to read it's rpm are the sivlerstone and artic cooler fan. The rest of the fan reads 0 rpm.

My board shows 45 nearly always, but goes to 48.  I have 6 fans on my case.  It gets higher sometimes, but I keep the room cool, i havent seen more than 50 yet.

So I have been having problems with sudden shutdowns.  I'm going along just great and BAM! the pc is off.  So anyways I was at first thinking it was a heat thing because my mobo temps were always high in the range that has been reported by those of you here.  
 
What I have found in all my reading and attempts to correct my problem is that my EVGA geforce 7800GTX card (installed in the blue pci-e x16 slot) had it's heat exhaust from its fan on the end of the card facing into the case.  I found a post that descibed that the temperature probe on this mobo (a8n32-sli deluxe) is right near where the exhaust from the vid card is.  The hot air from the vid card was blowing right over the temp sensor on the mobo and giving me an inflated temperature reading.  I replaced the stock cooler with an arctic cooling NV silencer 5 rev3 which exhausts the hot air our the back of my case and my mobo temps dropped about 5 degrees.
 
I am still having the problem with the shutoffs though I just thought I might be able to shed some light on the mobo temp problem.
 
If anyone has had a problem with random shutoffs with this mobo please let me know. I am still struggling to figure it out.  I always get shutoffs when gaming, but I also get them less frequenly when the pc is sitting idle.  My first thoughts were heat or a problem with the vid card due to the issues in games.  But I have solved my heat problems at least according to my temperature probes, and the random shutoffs when idle is what is really throwing me for a loop.  Please help!
 
~JEFF!

I've just "upgraded" to SLI, and also gone with the same motherboard as you!
 
In my Asus A8V-E SE my Athlon 4200X2 used to run at a cool 33 Degrees.  Chipset was reporting 31.  I could happily overclock the chip to to 2.4Ghz and the temp would rise to the low 40's.  All I did was replace the thermal compound on the northbridge with some AS5.  Cooling is:
 
1 80mm Akasa fan @ 1300 rpm @ back of case, just below PSU
1 Arctic Silence 64 Pro CPU cooler
Coolermaster PSU.
 
I was very happy with my old set up.
 
This week I decided to take the plunge and get me a new mobo with some serious overcloing potential.  I have gone the route of DFI in the past, but I was a little too daunted by all the options in the BIOS.  That and my first board was not compatible with my memory!  (it was when SLI was first released).
 
OK... enough rambling.  My point.
 
Since moving to this new A8N32-SLI Deluse motherboard:
- my memory is not as stable (cannot run stable at 2-3-3-6 @ 220 Mhz anymore)
- The CPU now only overclocks to 2.35 Ghz on stock voltage (I want to get a watercooling solution before I start over-volting the CPU, and then it'll  be an opty)
- The light in my Microsoft mouse plugged into my PS2 port doesn't go out during powerdown.
- The TEMPERATURES have moved up TEN DEGREES on the chipset and CPU.
 
I've changed the thermal compound on the CPU and the heatpipe cooling solution, and that has made no difference.
 
Granted, that if the temperature sensor is near my graphics card it should be warmer than previously, but my GFX card is only showing 37 degrees in windows!  This all seems a bit excessive to me.
 
Any clues?

  I have a simmilar problem. I just bought the A8n32-sli and 4200x2
 
My temps are around 40c Idle and jumps upto 53c when playing a game for a few hours. Case temp is about 37c. I haven't had my computer just shut down on me yet. Cuz i have good case cooling but it just seems like this core runs so hot. I dont understand it because from what i get from other people online they run in the 35 - 40c range.  I though i read somewere that just the 4200x2 runs hot on this motherboard for some reason.  I tried everything First i though it was a thermal paste problem, thinking i put to much on so i took it off and used a lot less. it seemed to drop by a few degree's but nothing significant. Then i figured maybe my heatsink was not disapating the heat quick enough. I have a thermaltake venus.  Slapped the retail on on there that one ran even hotter.  so i put the thermaltake back on because at least with that i can crank the fan way up and get the cpu temp down that and it seems to disapate the heat better because of the copper and more fins than the retail heatsink.  
 
I just dont know if it's a compatibility issue or what. my friend told me i should have gotten the 4400x2 because of the increased cache. but from doing some research it didnt seem like it was worth the extra 100 bucks at the time to get only a few more frames per second in my games.  But if this thing continues to run hot then i may try the 4400.
 
Edit:: yeah i forgot to mention. People were saying that it maybe a bad sensor reading but i used a infared thermomiter and pointed it at the core area on the heatsink and it read the same temp that the motherboard temp was detecting.

I also tried an Opteron170.  Same problem.
 
I'm suspecting a duff bios because the gfx seems to be corrupt.  The card works absolutely fine, and I've tried a known working 7900GT in there.  Same  problem.  I've since gone out and bought an ECS KN1 Extreme and so far....
 
NO PROBLEMS.
 
Guess it's an RMA job for me.

Same problem here.
 
AMD Athlon 64 X2 DualCore 6000+ 3.0Ghz
Asus M2N32-SLI Premium
nVIDIA GeForce 8800 GTS (Asus EN8800GTS)
Thermaltake VA8000BWS with 5 Fans
Zalman CNPS9500
 
On idle the MB is 47-48 and up to 60(!) when i stress it up.
The airflow inside my case is fine and i just can't figure out what causing  
the abnormal temperatures.
 
Does anyone know if the Cool'N'Quiet feature can help?