Strange overclocking problem.

[FalseChristian]

I don't know why all of a sudden it does this but both my cards do it (3dfx Voodoo5-5500 AGP and an ATI retail 128MB RADEON 8500).

When I overclock either of these cards the cards slow down by as much as 50% but rebooting seems to work most of the time and I get the 10%-15% increase I wanted.

What could be going on?

Thanks.