PSU or mobo issue?

[Rob Williams]

Hi all,

I have a weird problem I hope someone can help with. I have two different benchmarking rigs here, and the one I need seems to be rejecting certain GPUs, for some reason.

For example, I have two identical 8800GTS 512 cards, and one works just fine, but the other spawns a "Low power" error on Windows boot. If this was a problem with a single card, I could understand it, but it's not. Two different 8800GT's... one works, the other reports the same error. It seems to just pick and choose. However, all errors remain constant on this particular rig.

The GPUs are fine, however. When plugged into the other machine, they work perfect, so I am not sure what the deal is. Right now there is an 8800GTX installed and it works fine, and it's definitely the biggest power pig of a card I have here.. so if it works fine, anything should.

Does anything think this might be more of a PSU issue, or a motherboard issue? The PSU in question is an Antec 1000W:

http://www.antec.com/us/productDetails.php?ProdID=27100

Thanks guys, I appreciate any help!

[madmat]

Have you tried swapping the PCIE-G power plugs around to see if the warning migrates? In other words, swap the power cables from one card to the other and if it is indeed a power issue (on the PSU end of things) the warning will move from the card doing it in config a to config b (the configs in question are just the power cables being swapped).

Is there an auxilary power connection on the mobo? I.E. a four pin molex? If there is try hooking power to it. Also make certain that the last four pins on the 24-pin ATX connector are solidly plugged in. Some 20+4 connectors can be loose on those four even though the first 20 are solid.

Good luck.

[Merlin]

This power supply does not work with the new Nvidia G92 core. Such as an 8800 gts 512 OR an 8800 GT 512.
Antec, knows of the problem but will not let you RMA through them, and will not downgrade the power supply to one that works.

Some are saying to bend the two extra pins to the side ( 8 pin connection ) and plugging in with the 6 pins active.

contact the customer support department at 1-800-222-6832

[b1lk1]

Originally Posted by Merlin

This power supply does not work with the new Nvidia G92 core. Such as an 8800 gts 512 OR an 8800 GT 512.
Antec, knows of the problem but will not let you RMA through them, and will not downgrade the power supply to one that works.

Some are saying to bend the two extra pins to the side ( 8 pin connection ) and plugging in with the 6 pins active.

contact the customer support department at 1-800-222-6832

I agree. Antec has really dropped the ball with their high end power supplies and Nvidia cards. Even a 600W unit should easily power 8800 SLI.

[Rob Williams]

Originally Posted by madmat

Have you tried swapping the PCIE-G power plugs around to see if the warning migrates? In other words, swap the power cables from one card to the other and if it is indeed a power issue (on the PSU end of things) the warning will move from the card doing it in config a to config b (the configs in question are just the power cables being swapped).

Is there an auxilary power connection on the mobo? I.E. a four pin molex? If there is try hooking power to it. Also make certain that the last four pins on the 24-pin ATX connector are solidly plugged in. Some 20+4 connectors can be loose on those four even though the first 20 are solid.

Good luck.

I tried three different PCI-E connections... all the same.

Originally Posted by Merlin

This power supply does not work with the new Nvidia G92 core. Such as an 8800 gts 512 OR an 8800 GT 512.
Antec, knows of the problem but will not let you RMA through them, and will not downgrade the power supply to one that works.

Some are saying to bend the two extra pins to the side ( 8 pin connection ) and plugging in with the 6 pins active.

I just purchased this PSU for this purpose... so I can just bring it back. I don't think the 8-Pin trick would work, because I tested it also by plugging in the straight 6-Pin PCI-E cable it offers and still had the same problem.

I guess the question to ask though, is why does one 8800GTS work and not the other? Ditto with the 8800GT.

[madmat]

Is it not working in the same slot? That could point to a combination of PSU AND mobo incompatibility.

[Rob Williams]

Tested different slots as well... that's how I originally found out about it. It was the bottom card that was "faulty".

[madmat]

This is between the GT and GTS I take it. The only thing I can suggest is using a different PSU (such as that OCZ) and seeing if the issue resolves itself. It won't work if the board has to have dual 8 pin EPS connectors but some will work with either an 8 pin or 4 pin ATX 12V. I'd have to see the manual for your specific board to know if it's possible to do either or with it.

[Rob Williams]

Yeah, both the 8800GTS 512 and 8800GT card (both ASUS) have the problem. The Palit 8800GT and one of the ASUS 8800GTS 512s work fine.

The board requires two 8-Pin EPS connectors for overclocking, but thanks to Canada Customs, I didn't receive it yet, hence why I ran out to pick up this PSU. I can e-mail you the manual to the motherboard.

[madmat]

Cool, please do email it. And since you can run the board under stock speeds with an 8 pin and 4 pin I'd suggest trying another PSU just to verify the PSU as being incompatible with your specific setup.

[Rob Williams]

I don't have the time this weekend to swap out PSU's, and the only other one I have is an OCZ ~700W which is in my main rig, so I can't so easily move it. Manual e-mailed.

[madmat]

I read it and outlined the only way for you to verify the Antec as the problem in your system. I must ask, do you have the auxiliary molex power connected to the mobo? If not try that, it is a must have for cards greater than 75W.