eVGA 6800 GT overclock question?

[nathanheuer]

I just got a eVGA 6800 GT today and set about overclocking it. Coolbits put the card at 390/1.05 I tried pushing the core up more but would get artifacts at anything higher so I set the core back to 390 and set the memory up to 1.15 and it runs fine at this speed no artifacts ect. gaming temp is about 67 at this speed. I am thinking that perhaps my power supply is holding me back on the core speed? I only have a 350watt enermax in my system with 17amps on the +12v rail. What do you guys think? What watt power supplies are you all running to hit the 410+ core speeds? I realize of course that it could just be a core that wont clock as high but I know the Ultra needs bigger power supply to run at 400+ so I was thinking this may apply to my GT as well.

Thanks,
Nate

 

[Deskstar]

Your 350 Enermax must be a old one; most of them now come with greater than 26a on the 12v rail. Regardless, your 17a in likely too low, depending on the rest of your system power needs. First go to this link:
http://www.firingsquad.com/gui...power_supply/page2.asp
You may have a need for about 14.5a in your system. The 6800GT may need as much as 5a at max stress, eg overclocking, according to some other post. If so, then you need 19.5a, not 17a.
My own 6800GT is run always with a dedicated 12v connector to the primary on the card and a lightly stressed (eg fans/cdrom) power connector on the secondary. Do not split the primary; it is the primary source of power to the card. You must use the secondary connector, too. My 6800Gt runs fine and overclocked with a 22a @ 12v rail when set up as above. Try your 17a that way first, then buy a new supply second, then install the latest drivers (66.81), then consider an RMA if it has artifacts. eVGA has also posted a "revision" to its BIOS for that card that reduced the number of "bugs". Check your BIOS to see if it is the latest. If not, ask you might want to flash your video BIOS (not for a beginner however).