CPU temp

[wando red]

what temp should the CPU be.  Just put together my new box and CPU running at 85c.  Fans are running at full speed.  Its a Intel core 2 duo E840, 3 GHz.  Win7 64bit.

[DaveLembke]

85c is a bit hot for that cpu especially if at idle. Did you apply the thermal compound between CPU and heatsink, and is your heatsink the correct heatsink for the wattage rating of your CPU? Also does your case have adequate airflow. Such as if you run it with the side panel off of it and your temp comes down to normal 40c etc range you may need to add 1 or 2 fans to bring in cool air and exhaust the hot air. Also are you running native clock or overclocking? At least your CPU has thermal throttling, so that it wont china syndrome your socket and motherboard.

My first focus would be to make sure the heatsink is rated high enough to cool and that you dont have a dry CPU to heatsink flat causing the cpu to run hot.

[Geek-9pm]

Exactly what temp is he reading?
Use this program.

SpeedFan - Access temperature sensor in your computer
www.almico.com/speedfan.php
A program that can control fan speeds according to system temperatures.
Download

[TheShadow]

As a very old tech, (30 years and counting) I have one rule of thumb when it comes to heating of components.

If you touch it and quickly draw back your hand and say #%&@!!! (Ouch!!!!) then it's too hot. Eh?
Any time of any day, I can lay my digital heat sensor (index finger) on any component in my PC and it will feel no more than warm to the touch.  My favorite joke is "heck, my first wife ran hotter than my PC". 

It sounds almost like there is NO heat sink grease between the CPU chip and its Heat Sink.

Just my own personal preference, but since the old 486 days, I've used nothing but AMD processors.  Typically, they will run a lot cooler than the Intel chips, cost less, draw less power and come with a heat-sink and fan more than adequate to keep them cool.
I just ran Speedfan on my own PC and my CPU temp, after about five hours of run-time, is just 100°F.  Only slightly above human body temperature.  If I lay my finger on top of the CPU heat-sink, it actually feels cool to the touch.  That's normal.

Good Luck!
The Shadow 

[wando red]

I applied some compound and all seems OK.

a few years back when I purchased a CPU it came with fan and compound with instructions to apply compound.  The last 3 CPUs purchased have a fan but no compound.  And instructions do not say to apply compound.  The fans seem to have some kind of pre-applied substance on the surface where they contact the CPU.  Is compound still necessary?  I did do one previous without compound and it stays around 35c.  This one is a different story.

either way I guess I will always use compound.

[soybean]

And instructions do not say to apply compound.  The fans seem to have some kind of pre-applied substance on the surface where they contact the CPU.

Did that pre-applied substance have a clearly defined shape, which is typically square?  If so, it is probably a thermal pad, which serves the same purpose as thermal paste.  So, you could try using it or you could remove it and apply thermal compound.  But, don't simply put thermal compound on top of a thermal pad.  Pad vs. paste/compound is a topic of numerous forum discussions, like http://www.tomshardware.com/forum/267188-28-thermal-thermal-compound  You may find that discussion helpful.

[wando red]

yes, it was a pad.  I had problems with the computer so I had to remove the CPU a number of times.  I guess the pad wore thin.  I did clean it off the fan and CPU before applying the compound.

thanks for you help everyone.

[Salmon Trout]

I guess the pad wore thin.

Those pads are meant to work ONE TIME. If the heatsink is removed you should clean all traces of the pad from the CPU and from the heatsink, and use fresh compound.