Like Chris said, just set the threads priority low. IMHO, there is little point in playing games with Sleep. Just set the priority of the thread low and let the OS do it's job. If nothing else requires CPU, the math thread will get 100% of CPU which is exactly what you want. There is no point sleeping the thread when nothing else needs the CPU. However, since the thread has a lower priority, if pratically any other thread requires the CPU, they will get it. Tim Smith I know what you're thinking punk, you're thinking did he spell check this document? Well, to tell you the truth I kinda forgot myself in all this excitement. But being this here's CodeProject, the most powerful forums in the world and would blow your head clean off, you've got to ask yourself one question, Do I feel lucky? Well do ya punk?