MemTest 3.0
 

MemTest is a RAM reliability tester. It evaluates the ability of your computer's memory to store and retrieve data. A correctly functioning computer should be able to do both these tasks with 100% accuracy day in and day out. By running MemTest, you can ensure that your computer's RAM is correctly functioning. You can assign a number of megabytes to test.

http://www.hcidesign.com/memtest/