what can i notice if i lose stability, would system crash instantly on bootup? or how long should i wait till i see unsatability.
Well for starters you can run things such as; Prime 95, 3dmark 2k1-2k3 ( looping ( you will see under options) ) and Sandra burn in test..
P95 is your best bet for stability... ANY errors, and your overclock is either too high, or just needs some more juice.
and what is 5:4 ratio u were talking about? sorry if i ask too much, im still new in the overclocking world =)
The ratio's should be in your BIOS, reguarding what and where, i couldn't tell since I don't know the maker and what not...
But for instance, Your memory is really onlly capable 133mhz..(P4 willy's run a 400mhz FSB) 100mhz ( quad pumped ) = 400...
Since the multipliers are locked on the P4 your only way to go about overclocking is through the FSB...You can bump that 100->133 and reap the benefits.. Now lets just say, your chip can handle much more, but your memory cannot. You can run a 150 FSB on a 5:4 ratio...(divide 150 by 5 times it by 4) gives you a 120 FSB, well within stock speed..
Yet, you are running a 150x4 600FSB... Nice OC...

During this time is where you adjust voltages, temps and settings.
Hope that helps.
Good luck, and DON'T be afraid to come back and ask some more questions.
Welcome to the world of overclocking.