Bad Luck or Bad Driver?

I used a different drivers and they all gave me problems when I overclock. I am well aware that overclocking makes thing unstable but what concerns me was even if I was conservative with the clocks games would still crash. For example, the time between a (For 8600m GT DDR2 Vostro 1500) @500/420 crash and @550/450 crash are almost identical. BUT here's what troubles me the most! Every game when it crashes results in looping sounds and if I just tabs out of the game and wait for it to hit the desktop, the system would comes back to life and I can tab back into the game and play without problem for the remaining time until I close the game of course, and it depends on the game: it will either crash totally when I exit the game or exit the game perfectly without any issue. I have tried it alot of times with different games and it seems that TF2 was most sensitive to this particular problem, all I have to do was tab back/in and I can play perfectly until I decide to exit the game then it would results in driver crash nv4_disp not responsible or something along the line. It always results in a driver crashes, so at first I thought the problem might be bad drivers installation or just plain bad drivers but after trying a few other ones it seems the problem is else where. The temperature measured using i8kfan with a +8 offset only shows the card hitting 66 C at max, so I am ruling out overheating at this point. Here's my questions: Could it possibly be a sound driver issues? Will flashing the V-card Bios with the help of a guide on this forum make it more stable as I will not depend on the driver's stability? Could it be other factors? I am just jealous that others with the same machine or graphic cards can have stable OC while I always experience crash no matter how little the OC.

EDIT: I have tried drivers: 163.44, 163.74, 169.01, 169.04, 169.21, 169.28, Other games I tried includes: FEAR, GoW, Dreamfall: TLJ, COD4, and UT3. Some are more stable than the others, like FEAR and COD4 takes my OC better.

 

hmm,I guess this problem is just too weird for anyone to help?

Sorry for the double posting.

 

What are you using to OC with Riva or Ntune,ATI, Powerstrip?

 

I was using RivaTuner 2.06 with the above drivers. Does it matter which software I use to OC the card? If so, which one do you recommend out of the couples you mentioned?

 

Are you just cranking it up all at once? Or are you going in baby steps, 5mhz at a time?