Server Fault is a question and answer site for system and network administrators. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm looking for a command line application that will artificially burden the CPU. It needs to be better than just a busy loop. We're testing how the system holds up under heat stress and the CPU needs to generate as much heat as possible.

share|improve this question
A similar question is on superuser. Linux program to artificially create CPU usage – Zoredache Aug 10 '10 at 22:48

I've had good luck with:

dd if=/dev/urandom of=/dev/null bs=1024

It keeps a single thread at 100% CPU. Run multiple times to keep more cores busy. Nice it if you want to.

share|improve this answer
+1 .. That is pretty clever I think. – Kyle Brandt Aug 10 '10 at 23:39
Very nice usage of what's already on hand. – Skyhawk Aug 11 '10 at 0:06
This may keep the CPU busy, but will it really stress it? The various cpu stressing programs for windows seem to try a lot harder than just continually copying memory (maxed out SSE while driving the ALU and FPU). – deft_code Aug 11 '10 at 0:28
@Caspin It's doing more than just copying memory, it's doing quite a bit of computation as well. Doing the same from /dev/zero results in MUCH higher rates than from /dev/urandom, and CPU barely twitches. – sysadmin1138 Aug 11 '10 at 3:19
cpuburn is able to heat up the processor more quiekly as well as get it a few degrees hotter. dd 57° C vs burnP6 60° C. – deft_code Aug 11 '10 at 17:21
up vote 1 down vote accepted

Followed Zoredache's link. The question isn't really what I'm looking for. However, the accepted answer mentioned cpuburn.

*** WARNING ***
This program is designed to heavily load CPU chips. Undercooled, overclocked or otherwise weak systems may fail causing data loss (filesystem corruption) and possibly permanent damage to electronic components. Nor will it catch all flaws.

With a warning like that it's got to be good.
My one concern is it's a bit old. You'd think an app that used some of the new vector processing instructions could do a better job at heating up the cpu.

share|improve this answer

In conjunction with sysadmin1138's answer, try adding one of the distributed computing tools like Stanford's Folding@Home (*.

* I run f@h, and it generally keeps my laptop at 170-180F (I only run it when plugged-in, and not on my lap). I suspect it would would do similarly with a server CPU

share|improve this answer
It's not obvious from my question, but I need this utility to do heat test on an embedded device. While it's being cooked the only input is a serial line to verify the device is still alive. Would f@h run on a machine with no internet access? – deft_code Aug 12 '10 at 15:37
@Caspin, adding the "embedded" requirement definitely changes the scope of good answers :) – warren Aug 13 '10 at 14:06

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.