Is this the limit of my Gainward Geforce 3?

[gplracer]

I can run my Gainward Geforce 3 memory at 501 fine. I ran it at 511 and the screen instantly went white and locked up my computer. I had to reboot two times before the speed was put back on the default. Does this mean it is the limit of the card? I did not expect this behavior. I would have thought I would have seen video tearing first. I do have a athlon xp 1700+ and only an antec 300 watt power supply. Is there a setting on my epox 8kha+ to give the agp slot more voltage and should I do this?