Just shared this on another post, and it will help you as well.
Google: extreme power supply calculator
It is a great free tool for personal use to figure this out. There is none better.
Factor in capacitor aging when you calculate your power needs and bear in mind most power supplies are most efficient in the midrange of their rated power.
Sorry didn't see that, I'd buy a nice psu then. I mean it will work as long as your not running the psu at full load, but I personally wouldn't risk it
i post this question as i was having texture pop in problem in games ....and my psu is 4.5 years old ....i think this the prob ...i had tried every else ,,,,but havnt change my psu .......so what do u suggest