Acceptable temperature for Prime95 test

Not sure if this is correct forum but I got the link from here for hardware diagnostics for BSOD issues (from Usasma - Hardware Diagnostics )

I tried the blend stress test for Prime95 and the CPU temperature on both cores hit 100c within about 5 minutes so I stopped it. Idle CPU temp is between 40 and 45.

I have Lenovo X201 with Intel i7 M620 CPU @ 2.67GHz (not OC, all standard) with integrated Intel HD graphics and 8GB RAM. I've recently taken it apart to clean so I was wondering if this test is unsuitable for my laptop or if 100°C is OK or if there is some other issue I should worry about. I don't want to damage my laptop especially as I think my issues are probably due to driver support at 8.1 rather than hardware.

According to Intel's website, the maximum temperature that CPU can operate at is 105 degrees, so obviously 100 degrees after 5 minutes is getting very close to that figure.

When you do a stress test with Prime 95, there are 3 things you're looking for: -

1. Temperatures.
2. System stability.
3. That none of Prime 95's tests fail.

The test is designed to stress your computer, putting the CPU at 100% load, to make sure that it's stable and that there's adequate cooling. Most of the time you wouldn't be maxing out your CPU, although there may be certain occasions when you do, such as if you're doing multi-core video encoding.

So, in your case, I would say that the temperature is too high under load, but with a laptop, it's difficult to do anything about that. With a desktop machine you could buy a better CPU cooler, add more fans etc.

With a laptop, there's basically only 2 things you can do: -

1. Make sure that the the system is free of dust. If there's dust blocking vents, that can stop hot air escaping. Also, dust may clog up the fan and prevent it from working properly. You can use a can of compressed air to blow the dust out.

2. Reapply thermal paste. This involves taking the laptop apart, removing the heatsink from the CPU, cleaning off the existing thermal paste, then applying some fresh paste and putting everything back together. Incorrectly applied thermal paste can cause temperatures to be higher than they should be, and the type of thermal paste you use can make a difference too.

You can definitely do 1 easily enough, but whether you give 2 a try depends on how confident you are with taking your laptop apart. Also, bear in mind that taking it apart may void the warranty.

Hope that helps.

EDIT - Oh yeah, do you hear the fan kick in/get louder when you run Prime 95's tests? If not, there could be an issue with the fan itself, or possibly a configuration issue that is preventing the fan from speeding up.

Thanks for the reply. I recently took the laptop apart to clean (I do one a year or so) and it was OK.

I just tried running the test again and notice the fan doesn't seem to speed up although the air out of the exhaust vent gets hotter. It is hard to tell as it is very quiet. I'll look into this (download some monitor) and if not think about the paste thing perhaps.