First time overclocking advice

[Aleatoire]

Ok so this is my first time overclocking. I have a GTX 260 that I want to overclock using Rivatuner and I have a few questions.
I know its pretty hard to screw up but I just need to clarify some stuff.

Ok so, at the moment my GTX 260 is factory overclocked and I have a Vantec Ion2 620w PSU. I would like to know as a rough guide what I can safely set my speeds at without damaging anything and whether my PSU will be enough.
The problem with the power supply is, when I got my GTX 260 I spent a long time working out if my (then 520w) PSU would be able to handle it. I found numerous answers saying an easy yes, so I went ahead and used it. It seems that the PSU wasn't after all enough and I ended up having to buy a new one.
So what so what I want to know is that if my 520w power supply wasn't enough to handle my GTX 260 at factory speeds, then will my 620w PSU be enough to overclock to a sufficient amount that there will be a noticeable performance difference, without any risk of frying my PSU.

My specs if you need them:

Intel Core 2 Duo E7500 @ 2.93ghz
4gb OCZ Gold Edition 1066MHz
1TB WD Caviar Greenpower
Asus P5Q-SE2
Vantec Ion2 620w
Asus Nvidia Geforce GTX 260
Santa Cruz Turtle Beach 5.1

Any help would be great as well as any advice about my first overclock.

 

[riz89]

Well firstly, your card will use up at max around 180W. My guess is that your PSU will suffice. I have a 800W PSU with CF and I have no problems so far. However if you can, then swap you 620 for a 700W or 750W PSU, just incase.

For OC-ing, you might want to first check with the manufacturers website cause they have OC programs that are built specifically for their cards or else you can always go for nVidia's software. Or you can just ditch all that and use Rivatuner and Furmark.
Best method to set over clock would be to make increments of the Core clock speed and memory and running furmark after each adjustment. Always make sure you finish with the Core clock and then move onto memory. Keep doing this until you start seeing artifacts. When you do, then change the setting to the previous one and test again.
If your too busy use the cards software to do it automatically like CCC for ATi

 

[jsc]

I wouldn't expect too much more from a factory overclocked card.

 

[riz89]

I have a factory over clocked card..i managed to OC it till 700/1100..no probs whatsoever...

 

[unclefester]

I used these 2 tools for OCing my 260 http://www.evga.com/PRecision/ and this http://www.download25.com/install/video-card-stability-test.html

The stability test runs in a small window and you can adjust EVGA precision with your keyboard while the program is running. As the world turns just keep watching for artifacts and watch temps, this little program will have your card up to full temp in about 30 seconds. I recommend setting your fan speed to at least 80% before starting.