Motherboard too hot?

ASUS P5B-E
intel core 2 duo E6600
nvidia geforce 8800gts 320mb
2x1GB DDR2 PC800
2x512MB DDR2 PC800
2x320GB 7200 SATA HDDs
SATA dvd burner
case: Newegg.com - COOLER MASTER Centurion 5 CAC-T05-UW Black Aluminum Bezel, SECC ATX Mid Tower Computer Case - Retail (http://www.newegg.com/Product/Product.asp?Item=N82E1681 1119068)
power supply: Newegg.com - COOLMAX CR-550B ATX 550W "140mm Fan" Power Supply 115/230 V UL, CSA, FCC, TUV - Retail (http://www.newegg.com/Product/Product.asp?Item=N82E1681 7159033)

running the ASUS pc probe, I get a temp of around 49C on the motherboard when idle - the default alarm threshhold is 45C. CPU runs at 43C. CPU fan runs at about 2000rpm, chassis fans at 2000 and 1200. No overclocking, all default settings. Checked the airflow and it seems to all be going from front to back as expected; no fans spinning the wrong way.

Any ideas what could be wrong to make it alarm when idle?

Take off side of the case, put a fan next to it, check your temps. If they go down considerably, you need better case fans (RPM != airflow). If not, it's probably a broken sensor.

alright, tried that and with a big ass fan the temp is down to 30C.

ugh, i bet the problem is the huge ass video card making a barrier between the mid+top and bottom of the case..

Well, by the looks of it you have an 80mm fan sucking air in at the front, while a 120mm and 140mm fan are blowing it out at the back, which is pretty damn unbalanced. Try a more powerful front fan, as well as an extra fan on the side in place of the duct.

yeah, I'll see what I can do about getting something beefier in the front

You may also want to think about changing the heatsink on the northbridge. I have the P5N-SLI and was having heat problems until I changed the nb heatsink to something that actually worked. I use the Noctua chipset cooler (http://www.driverheaven.net/reviews/Noctua%20chipsetcooler/index.php) and it works great.

Can't see to well from the pictures, looks like the front 80mm fan sits inside the case and not next to the very front of the case, also does it have unrestricted airflow from the font of the case or is that grill mesh on the front just for looks?

using the cpu cooler that comes with the intel processor?

Something like this might be in order

Newegg.com - Scythe KAMA BAY SCKB-1000WH 120mm 120mm Fan for 5.25" System Cooling - Retail (http://www.newegg.com/Product/Product.aspx?Item=N82E168 35185019)

One other thing, if you applied thermal compound to your CPU, did you do it right?

Arctic Silver Incorporated - Arctic Silver 5 Instructions (http://www.arcticsilver.com/ins_route_step2intelas5.h tml)

replaced the front and back fans.. now it seems a lot better, though louder.

One other thing, if you applied thermal compound to your CPU, did you do it right?
CPU wasn't a problem, it was actually cooler than the MB

I'm having the same issues pretty much with the same mobo. My CPU temp is 42 C and my mobo temp is 41 C (it's 84 F in the room right now, really hot I know)

I have 4 fans, 120 mm on the front, an 80 mm inflow pointed at the vid card, and an 80 mm sucking out the back and side.

It appears that the mobo heatsinks need fans to help cool them down the best.

I'm having the same issues pretty much with the same mobo. My CPU temp is 42 C and my mobo temp is 41 C (it's 84 F in the room right now, really hot I know)

I have 4 fans, 120 mm on the front, an 80 mm inflow pointed at the vid card, and an 80 mm sucking out the back and side.

It appears that the mobo heatsinks need fans to help cool them down the best.
side fan should be intake

side fan should be intake

1 is intake, 1 is out..

Intake is by the vid card, and the out is right above that a bit by the cpu

1 is intake, 1 is out..

Intake is by the vid card, and the out is right above that a bit by the cpu

got a reply from asus saying that these boards normally operate at 35-55C, so I wasn't really in any trouble to begin with

How hot is too hot for the nortbridge controller on your typical intel p965 motherboard? 50c?

edit: under load of course.