Reoccuring PSU/GPU problem, help!

Dem · 01-25-2006, 06:31 PM

Okay, I've got a problem that I can't seem to solve.

Just over a month ago, I could not get a display from my computer when I boot it up. Everything was working as far as I could tell, but I couldn't get a display on the monitor with my BFG 6800GT while my (really) old Stealth Video Card worked fine in it's PCI slot. Assuming it was the video card, I sent it back and had it replaced. BFG sent back a 6800GT, but it was the kind with 2 DVI ports instead of 1 VGA and 1 DVI (not sure if the power requirements are different).

I put the new video card in and the computer worked... for one night. I shut down the computer, and 10 hours later when I started the computer, the same problem occured. My theory moved to a faulty PCI-Express slot on the motherboard, and had the mobo replaced. Again, I put the new (identical) part in and it worked for one night. I shut down the computer and 20 hours later I had the same problem. Frustrated, I tried swapping out video cards, monitors, DVI cables, all with no results. Finally, I noticed that when I started the computer, the video card was not powering up. My theory again moved, now to the power supply. Checking the voltages with a multimeter, I found that the 12V rail was fluctuating rapidly between 10 and 11 volts and the 5V rail between 3 and 4 volts.

I had the PSU replaced and put the new (identical) PSU in, and booted up. The voltages held at 11.9 and 4.8, but the video card didn't power up. I shut it down and started up again, and the video card worked! I watched temps and did some driver installation before shutting down the computer. Like clockwork, the next day, the computer had the same problem. The video card won't boot up. And now, when I check the voltages, the 12V rail has dropped to 11.36 and fluctuating to 11.75. The 5V rail has developed similar drops.

5 weeks and 3 RMAs later, I'm completely frustrated and regretting building my own computer. I can't figure out what's wrong. Either Seasonic makes crappy PSU's that can't handle the power needs of the 6800GT, or the 6800GT is so power hungry it's damaging the PSU. I'm pretty sure that on paper, they should be able to handle each other (especially since I have minimal other parts using power), but it's obviously not working. I don't know what's at fault, and I can't obtain other GPUs or PSUs in the same class as I have to run control groups without buying new ones.

Anyone have ideas about how to fix this? After it failed again yesterday, I almost put my fist through the wall.

Dngrsone · 01-25-2006, 06:51 PM

What are the amperage ratings for the power supply, and what does the video card documentation want? IIRC, the Neo4 requires minimum 16a and the 12v rail, I'd consider 18a the min.

I have the Neo-4f with a Winchester 3000+ and MSI 6800GT. My PSU has 18a on the 12v rail and total output 550W... I wouldn't doubt your PSU is underpowered.

Dem · 01-26-2006, 02:36 AM

It's possible.. I think the S12-500 is rated @ 17A and 16A..

I think I'll buy this:

http://www.newegg.com/Product/Produc...82E16817703001

If that doesn't solve the problem, then I guess I'll know it's the video card.

01-25-2006, 06:31 PM	#1 (permalink)
Dem New Member Join Date: Dec 2005 Posts: 21	Reoccuring PSU/GPU problem, help! Okay, I've got a problem that I can't seem to solve. Just over a month ago, I could not get a display from my computer when I boot it up. Everything was working as far as I could tell, but I couldn't get a display on the monitor with my BFG 6800GT while my (really) old Stealth Video Card worked fine in it's PCI slot. Assuming it was the video card, I sent it back and had it replaced. BFG sent back a 6800GT, but it was the kind with 2 DVI ports instead of 1 VGA and 1 DVI (not sure if the power requirements are different). I put the new video card in and the computer worked... for one night. I shut down the computer, and 10 hours later when I started the computer, the same problem occured. My theory moved to a faulty PCI-Express slot on the motherboard, and had the mobo replaced. Again, I put the new (identical) part in and it worked for one night. I shut down the computer and 20 hours later I had the same problem. Frustrated, I tried swapping out video cards, monitors, DVI cables, all with no results. Finally, I noticed that when I started the computer, the video card was not powering up. My theory again moved, now to the power supply. Checking the voltages with a multimeter, I found that the 12V rail was fluctuating rapidly between 10 and 11 volts and the 5V rail between 3 and 4 volts. I had the PSU replaced and put the new (identical) PSU in, and booted up. The voltages held at 11.9 and 4.8, but the video card didn't power up. I shut it down and started up again, and the video card worked! I watched temps and did some driver installation before shutting down the computer. Like clockwork, the next day, the computer had the same problem. The video card won't boot up. And now, when I check the voltages, the 12V rail has dropped to 11.36 and fluctuating to 11.75. The 5V rail has developed similar drops. 5 weeks and 3 RMAs later, I'm completely frustrated and regretting building my own computer. I can't figure out what's wrong. Either Seasonic makes crappy PSU's that can't handle the power needs of the 6800GT, or the 6800GT is so power hungry it's damaging the PSU. I'm pretty sure that on paper, they should be able to handle each other (especially since I have minimal other parts using power), but it's obviously not working. I don't know what's at fault, and I can't obtain other GPUs or PSUs in the same class as I have to run control groups without buying new ones. Anyone have ideas about how to fix this? After it failed again yesterday, I almost put my fist through the wall. __________________ AMD Athlon 64 3500+ Venice MSI K8N Neo4 Platinum 2Gb Corsair XMS PC3200 BFG Tech 7800GT 510W PC Power & Cooling ATX-Deluxe Seagate 160Gb

01-25-2006, 06:51 PM	#2 (permalink)
Dngrsone VIP Member Join Date: Dec 2005 Location: Centrally located far from everywhere Posts: 544	What are the amperage ratings for the power supply, and what does the video card documentation want? IIRC, the Neo4 requires minimum 16a and the 12v rail, I'd consider 18a the min. I have the Neo-4f with a Winchester 3000+ and MSI 6800GT. My PSU has 18a on the 12v rail and total output 550W... I wouldn't doubt your PSU is underpowered. __________________ Dngrsone Saving lives, one protein at a time. Team 12912

01-26-2006, 02:36 AM	#3 (permalink)
Dem New Member Join Date: Dec 2005 Posts: 21	It's possible.. I think the S12-500 is rated @ 17A and 16A.. I think I'll buy this: http://www.newegg.com/Product/Produc...82E16817703001 If that doesn't solve the problem, then I guess I'll know it's the video card. __________________ AMD Athlon 64 3500+ Venice MSI K8N Neo4 Platinum 2Gb Corsair XMS PC3200 BFG Tech 7800GT 510W PC Power & Cooling ATX-Deluxe Seagate 160Gb

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