Help req for overclocking my 4600ti

[xirokx]

Hi,

I have a nvidia 4600ti which I am trying to overclock, I am a n00b in the overclocking world so please bear with me....

I have installed coolbits and then attempted to increase the CPU clock frequency and the memory clock frequency in the clock frequency section....

Current settings:

CPU 300mhz
Mem 650mhz

I was increasing both speeds by 5mhz then "testing the settings" to ensure it would work

I hit a nerve at:

CPU 360mhz
Mem 710mhz

Meaning my pc rebooted at this stage so after rebooting I went back in and stopped at:

CPU 355mhz
Mem 705mhz

However when I tried playing COD2 online after clicking on the icon on my desktop the screen went all black???

So I thought let me half these and then test it so at:

CPU 320mhz
Mem 680mhz

the game loaded fine however when the first game screen appeared it went all funny so I rebooted.....

What am I doing wrong?

I dont have an detect optimize settings option in the clock frequencies section which I found strange as I was advised to select that....

Any ideas?

Thanks for any responses I recieve....

P.S system details are as follows:

AMD 64 3500 newcastle clocked from 2.2ghz to 2.4ghz
1gig ram
nvidia geforce 4600 ti