Hi, all I just overclocked an 3.4 GHz Northwood CPU to 3.91GHz, but it is only a bit unstable. The temps reach as high as 47 Celsius. Any ideas of how to make it run cooler at this speed. Any coolers that might be better than my Zalman CNPS 7000 copper cooler?

Im Not sure about coolers, but if u want it to that far i think u can use Water Coolin system, that will do the work.

Alex~

Watercooling is too expensive and risky. A good wc system is about 300 bucks

If your peak CPU temp is 47C, this is actually very, very good and well below what most overclocking runs. Most norties are quite happy in the mid 50's so your 47C peak is ideal.

If this is your env/mobo temp, you should look into better case cooling to drop this a tad. It's a bit high for env temp.

If you want to go more extreme with air cooling/overclocking, THE status quo for Socket 478/Nortie overclockers is of course, the Thermalright XP-90 series copper heatsinks and Panaflo 92mm fan combo (and AS5, of course). It's a very expensive combo, but you can usually "to the moon" overclock these norties and drop peak temps to 39-42C at extreme overclocking rates.

Nice link here of how well this combo works in practice:
http://www.silentpcreview.com/article194-page3.html

ZALMAN 9500 http://www.newegg.com/Product/Product.asp?Item=N82E16835118003

And getsome Arctic Silver 5 thermal paste
http://www.newegg.com/Product/Product.asp?Item=N82E16835100007
or
http://www.newegg.com/Product/Product.asp?Item=N82E16835100008

already have as5 on it. MY CPU IS SOCKET 478 CPNS 9500 Doesn't fit

My CPU temp is 47 Celsius and mobo is 29 Celsius. But anything above 47Celsius restarts my pc. Even if I increase the voltage

http://www.newegg.com/Product/Product.asp?Item=N82E16835118221 Thats 478 P4, 120mm for more airflow.

Yeah I will buy that, I was thinking about it, but from 47 peak Celsius how much would it lower it.

So your PC will turn off at 47? Sounds like you need to up that in BIOS. 47 is a bit toasty for a northwood but nothing to be worried about by a long shot. Also, what is the stepping on the CPU?

Another thing, have you run a burn in program to test stability? What else is unstable? If the only problem you have is heat, then I dont see why to worry.

Hi, how do I turn it up in the bios. Also after running 3dmark06 at the cpu test the pc restarts. In games and anything else it is stable. Stepping is 9

Well what Mobo are you using? It should be easy to find, I am sure the manual will mention it. But if you crash druing 3dmark you do not have a stable OC.

I have an ASUS P4C800 Deluxe. It does not mention anywhere in the manual

The restarts are likely not due to temperature but a problem with memory/memory timings.

Every Northwood I've ever tweaked cold hold and sustain 55C with complete stability.

Reboot/resets are usually due to memory unable to hold the higher FSB speed. Try backing down latency or upping voltage.

Thanks, sooo much man you were right. I changed the DRAM Idle Timer to 0T from Infinite, and the Dram Refresh Rate to 64uSec from 7.8usec. Now it is rock stable in 3dmark 06 and 05 in cpu tests ( ran them like 12 times) not one freeze or restart. I will try to run prime 95 to see how long it can run without problems, and I will post back the results. I will post maybe in a couple of hours. Just to let you know I am at 3.91 GHz on air cooling, and CPU is 3.4 GHz Northwood 30 cap. I tried 4.01 GHz, but I have to up the voltage to 1.70, and after a couple of minutes it freezes. Oh well there is no difference between 3.91 GHz and 4.01 GHz