How to I find most stabel oc on 4850?

[pcnoob101]

its defukt clock is 650/1000 and Im looking to get it to a stable OC with no BSODs.
I can run games for 20 minutes sometimes on what CCC gives me as max(700/1200) but then BSOD after a while. furmark seems stable but in game, BSOD...
should I use auto tune and leave it for an hour or so?
tips?

E4500 @ 2.2
3GB DD2 @ 667
HIS 4850 ICE Q4 @ 650/1000
all stock cooling with a 92mm fan sucking all hot air out and cold air in. no heat issues, forutnatly.

 

[outlw6669]

Starting from stock, overclock the Core 5-10Mhz at a time.
Check for stability using ATI Tool for ~15 min before clocking it higher.
When you reach the limits of the Core, repeat for the RAM.
After you think you have a stable overclock, try an 8 hour stint of ATI Tool and see if there are any errors.