jinsonxu,
I have this program on my webspace that gives you a pretty good idea of whether or not your system is stable. It tests all the major parts of system, very thoroughly, and can be left running for days to get a very accurate yes/no answer.
Stability test program
Its fairly simple, just unpack it to a temporary directory and run the test program, its fairly eas to use and figure out. Basically, when you stop testing, if the system reports XX amount of tests and 0 errors your ok - but you should let it run for a few hours at least. Be warned, if your cooling isn't up to scratch, you will know now.
If you want, you could run the RC5 client in the background while performing the test, but it wont make much difference as it will get no CPU time (the test is 100% CPU intensive), so shouldn't have much of an effect on the result.