I was wondering if the screenshot below of Rivatuner monitoring my graphics card's current could tell me if my PSU isn't quite up to the job? When it's idle the power draw is a 99% straight line around 10.91A, but when I use AtiTool to stress it the power is all over the shop. It seems to "want" to take 41A but slips back to 32A in intervals, as seen below. Is this normal operation, probably a lack of PSU power, or could be either?
Ah, I think I've found my own answers. I was about to say that it exhibited the same behaviour at stock speeds (first picture is overclocked), but then I also checked it at much slower speeds with a draw of around half the first one. Result? Same jumpy lines on Rivatuner. I'm pretty sure my PSU can handle it at such slow speeds.
My conclusion is that my PSU is fine at the stock speeds of my graphics card. It it also probably the inhibiting factor when it comes to overclocking. If I stress my graphics card 100% at stock, it won't go above 66deg. But if I overclock and play a relatively old game, it will quickly BSOD/lockup, even though it may be below 60deg. Heat is presumably not the issue. I would guess the inhibitor is my PSU, as the card was owned by a friend in a different system, who got stable overclocks far beyond mine.
So, perhaps PSU can't take the OC. So be it. My main worry was the PSU couldn't hack it period. The entire computer will be ripped apart and dumped into a Word/IE screamer within the next 9 months anyway, so I'll survive.