Graphics Geforce 6800 Ultra PSU requirements

I am currently running this rig:

MSI K8T Neo2 FIR
AMD Athlon64 3500+ (2.2GHz)
XFX Geforce 6800 Ultra
200GB Maxtor DiamondMax9 7200RPM P-ATA
120GB Maxtor DiamondMax9 7200RPM P-ATA
200GB Western Digital 7200RPM S-ATA
Plextor PX-716A DVD-writer
Creative Soundblaster Live! Player 5.1 (old, but still working!)

.. aaand I'm having problems with feeding it sufficient power. When I first installed this motherboard, CPU and graphics card, I was running it all on an old Lepont 320W PSU. This caused one of the harddrives to shut down randomly, so I bought a new PSU - a Thermaltake 480W Purepower.

Unfortunately - it doesn't seem to be much better. When I play games that stress the 6800U (I have noticed this behaviour in both Far Cry and World of Warcraft when running high details. Strangely enough, DOOM3 runs just fine), I'm experiencing random lockups. Sometimes the picture freezes for 30 seconds before returning to normal.. sometimes it just hangs completely.

I have, after a long night of googling and troubleshooting, narrowed it down to my PSU. The Thermaltake only has one 18A 12V rail, which I suspect isn't enough. When running the harddrives off a separate PSU, Far Cry seems to work just fine. Doesn't this sound like a power issue to you too? I know it's not the wattage tho - while the Thermaltake is rated at 480W, it has a peak effect of 550. After a lot of reading, I've learned that the recommended minimum amperage on +12V is 18A for 6800U cards.

Now my question is this: I can still return the Thermaltake and get another PSU. What should I get? I'm currently looking at an Enermax Noisetaker 485W, which has a total of 32A on two separate 12V rails (http://www.enermax.com.tw/products_page.php?Tid=1&gon=256&Gid=18&Gid2=43). What do you guys think?

 

well nvidia did originally say that a 480w PSU is what a system with 1x hdd and 2x optical drives needs. going by what your running its not enuff. might be worth getting a 600w PSU or mod the case and have a crappy 300w power the HDD's and stuff

 

Either a Tagan 480W or the Enermax 485W should be fine, they have nice strong 12V rails and the voltages are rock solid (Plus they are well priced). You just couldn't go wrong.

Cons:
Enermax - Stiff pre-braided cables
Tagan - Some people have experienced a faint 'clicking noise' which seems to be coil noise but its not a common problem.

 

600W eh. This is really starting to hurt my wallet

Any thoughts on the amperage requirement? I'm now looking at a Thermaltake Silent Purepower 680W with three +12V rails, going at about $200. But at the same time I'm noticing that these three are 15A, 15A and 8A respectively. If the mainboard gets a 15A, the 6800U gets a 15A and the drives get the 8A, will this be enough?
The stores around here have an OCZ PSU rated for 600W as well, with a whooping 32A +12V rail. But at $300 it's just too costly.

Edit: Thanks for the quick replies by the way. Well yes, even though the Enermax only has 5 more watts, the +12V rail is (in total) about 75% stronger. The 480W Tagan with a 28A +12V rail is only $120, which is good pricewise. I really don't want to order yet another one and experience the same problems

 

They downed that to a quality 350w unit. And adding an extra drive or two won't equate to another 100w.
Thermaltake PSU's aren't exactly the best. Get a nice antec or something with a strong single 12v rail if you ask me (I'm still in SLI mode regarding PSUs which hate dual rails, shouldn't matter as much for single PCIE or AGP though). 18a should be plenty but I'm confident that Tt overrates their PSUs (ie gives max rails at 20c, not the 40-50c the inside of a PSU will be at)

And for God's sake DON'T run a crappy 300w for your hard drives. Crappy PSU + hard drives = lost data and dead drives!

If it doesn't do it in Doom3 but does in FarCry and WoW, I'd think it may be a driver problem... most likely DX9 (I think WoW is DX, I know D3 is OGL). Get the latest non-beta drivers and whatnot (66.93 I think) and give that a try if you haven't already.

 

In addition to changing my PSU to a OCZ PowerStream 520W with two 12V rails rated at a total of 33A, I'm now running a clean Win (formatted my hd yesterday) with all the latest drivers (except the VIA 4in1 pack). Although my previous Windows install was only about a week old, I got suspicious when Splinter Cell: Pandora Tomorrow plainly refused to load at all.

Now the first thing I did after formatting was to install DX9.0c and the latest official nVidia drivers (66.93, which I was running before too), and then Far Cry. So far I've been unable to reproduce the freezing.

It has occured to me too that it might be a driver problem, as I've only experienced it in DX games, but my attention turned to the power after running two separate 350W Fortron/Source PSUs simultaneously made the freezing go away.

Anyway, it seems to be working now. Thanks a lot!

Update: No, it's not. Argh. In addition, I now know that it also happens in OpenGL. I can't make DOOM3 freeze, but the computer just froze as I was playing around with an open source game engine using OpenGL. I've tried just about everything, except for another GFX card. If that works, I'm returning the card. Trouble is, the problem is hard to reproduce