Sounds like your card is protecting its self from damage and clocking down on you,
but i heard it does that around 97 degrees Celsius so i dunno..
I have that same card and overclocked it a bit so i might be able to help.
First off lets not forget its ALREADY overclocked from the factory..
google the 550 reference clocks and see what i mean ;)
Also when i overclock this card with evga software or any others,
i get 0 artifacts and i simply get a driver crash (when gpu pushed too far)
and im using 301.42-desktop-win7-winvista-64bit-english-whql
i never did try the previous driver i just bought my card.
So with stress testing to make sure its stable the most
i can overclock this thing to is 971/2188 (at stock voltage)
if i put the core to 1,000 my OS crash's and lockups instantly and i have to reboot !
So i wouldn't jump up straight to a 1,000 if i were you
start at 10mhx increments and test for a bit then move up some more.
The clocks i mentioned (max) are within about 10/15mhz of causing errors,
so i wouldn't expect anyone to get more than that at stock voltage.
I can't say anything about higher voltage speeds though
i havn't tried that yet and i'm not too interested
it makes me a bit nervous over volting, even though i do it 24/7 on all other pc parts.
I'd love to be able to get it running at 1055/1260MHz http://hwbot.org/hardware...rd/geforce_gtx_550_ti/
but i don't know what this guy has done etc
Lastly i did experiments with covering the outtake exhaust inside the case
and it made the temps way worse.
Although putting electrical tape to seal the fan so only air can escape
through the two exits seemed to help it blow air better :)
i also got a bit of improvement on load temps when i re applied the TIM paste
i used Arctic Cooling MX4
oh and i was suprised at how well the TIM paste was applied from the factory
they seemed to use something that looked and felt like Artic Silver or AC MX
and the application of it seemed pretty good, maybe a tad on the too much side
but i would tell people don't worry about the TIM on this gpu and only replace it if you
really want to because its perfectly fine from the factory :)
post edited by xpmule - 2012/06/07 08:09:54