I have never used linux, so i don't know if this will work for you, but a very easy and cheap way to test full load in Windows is to use the calculator and type in 15000, then hit the n! key which is under the scientific part of the calculator. I'm not sure what it does, but it runs the CPU at full load trying to finish the calculation, it takes anywhere from 10minutes to an hour or so. So if you have a scientific calculator with that key in linux then give it a try.