6800Ultra not enough power-PSU problem?

FACTION95Si · May 31, 2005

Over the last couple days when I'm gaming I've been getting windows messages saying my 6800 Ultra isn't getting enough power so its performance will be reduced. Before I cleaned up my system I would get random BSOD followed by a system reboot when in the middle of a game.

My power supply is an Antec Truepower 550 and its about 2 years old. Im running the following:

Asus P4C800EDlx
4x 512 PC4000
P43.0C @ 3.3GHz
BFG 6800 Ultra
2 optical drives
4 hard drives (2 PATA, 2 SATA)
3x120mm fans
92mm Panaflow cooling the XP-90C
2x 12" cold cathodes
Sunbeam Fan controller

Could my powersupply be overworked and not giving the video card enough juice? Can anyone give me some tips on how to diagnose my problem?

dicecca112 · May 31, 2005

Could you give us you rails at load, looking at your system and the PSU, I wouldn't think that it would be a power problem. How is the Card being powered, is it on its own run of molexs or at least the first in a run?

FACTION95Si · May 31, 2005

When I get home tonight I'll screen shot MBM5 and post it. I have 2 separate runs or nodes going to each of the power plugs on the Ultra.

larva · May 31, 2005

It's very possible your supply is showing its age. I find the cooling to be inadequate for 100% load on these models, and you're getting close to that (if not there). A bunch of caps swelled up and leaked on my TP430 in the output section, and it wouldn't surprise me if yours are swollen also. They undersize these caps physically to make them fit the available space, and in conjunction with fairly innefective cooling they can fail with stiff loading.

larva · May 31, 2005

BTW-If you have proof of purchase you can RMA your supply to Antec for a revised model with increased capacity on the 12V line. The new models are supposed to be much better.

FACTION95Si · May 31, 2005

Hey Larva good to see you posting.

As far as the PSU I voided the warranty when I opened it up to rewire the fans to run off my fan bus. At stock they never spun fast enough to get any air flowing through the unit.

As far as a new unit what would you recommend?

noxqzs · Jun 1, 2005

Im pretty much running the same exact setup. (3.0c @3.6, and 6800u @ 480/1250, 4 120mm fans and wc pump) There are 3 SCSI drives and 2 optical drives also, I find require a lil more juice than ATAs. The PSU comes nowhere close to stressing. One thing I dont have is the cold cathode light installed, but I do have one and those things do not draw that many amps. The Temperature of the transistors in the PSU are 10* above case. Looking at the MBM logs, the voltage hasnt dipped below 5.4, and 12.3 and this is for a 2 week log.
This is the Antec 550 20pin ATX we talking about?

FACTION95Si · Jun 1, 2005

Yep I'm almost positive this is the same PSU as yours noxqzs. I did a little further research yesterday and found that when the unit gets hot it puts out less power. The last couple days that I have had the power problem with my video card I have been running the psu fans at low voltage probably 5V or so. This leads me to believe the fans aren't pulling enough of the hot air out which is causing the unit to heat up and make less power. I'll runs some tests tonight on the rails to see how stable they are. What do you think of my theory?

SolidxSnake · Jun 1, 2005

Just get better fans. Maybe drill a few vent holes near the caps?

Electron Chaser · Jun 1, 2005

Before you break out the power tools. Grab your meter first and post what your 12V rail is under load. Not all Antec TPs are created equal even if they are they same model. Like Larva I to had a 430 TP that I promptly dumped when it started giving me problems.

noxqzs · Jun 1, 2005

checking the rating with your own meter is the only sure way faction. they are relatively inexpensive also for basic models. with the heatsink you have, does the psu intake fan sit right above the XP-90C. The heatsink fan might be pulling all the cool air away from the intake of the psu. Is so, mountin a 120mm fan right above the heatsink on the door could help

Daddyjaxx · Jun 3, 2005

You sure one of the molexes hasn't come unplugged. I noticed that message when one worked its way loose on me.

shellshock · Jun 3, 2005

SolidxSnake said:
Just get better fans. Maybe drill a few vent holes near the caps?

ya, i agree, keep that thing cool so it wont throttle its self

d94 · Jun 3, 2005

that would also void the warrenty

larva · Jun 4, 2005

FACTION95Si said:
As far as the PSU I voided the warranty when I opened it up to rewire the fans to run off my fan bus. At stock they never spun fast enough to get any air flowing through the unit.

As far as a new unit what would you recommend?

I replaced my TP430 with a TPII480, but they botched the cooling even worse on these units. Once the cooling is fixed (and at this juncture, the only place I know to get an ideal fan is to rob one from a Fortron), the TPII's are great. But it sucks to have to void the warranty to fix what should have been right to start with.

This leaves a few options: Fortron AX500-A (superior bang/buck at just over $70 at some places), FSP 550 (massive 12V urge, if you can hang w/the 80mm fan), OCZ PS520 (pretty good on all counts), or one of the s12 Seasonic units (pretty pricey, but pretty nice too). A lot of this depends on how much money you are looking to spend--if you limit yourself to say, $75, the Blue Storm is without equal. If you move up to $100, the FSP550 is a good option. If you further allow $120, the OCZ is pretty spiffy. And if cost is no object, the Seasonic is a really good unit with a really good fan.

larva · Jun 4, 2005

noxqzs said:
This is the Antec 550 20pin ATX we talking about?

Yes, but if yours is of the new revision it is not comparable (not that I know which it is).

larva · Jun 4, 2005

FACTION95Si said:
Yep I'm almost positive this is the same PSU as yours noxqzs. I did a little further research yesterday and found that when the unit gets hot it puts out less power. The last couple days that I have had the power problem with my video card I have been running the psu fans at low voltage probably 5V or so. This leads me to believe the fans aren't pulling enough of the hot air out which is causing the unit to heat up and make less power. I'll runs some tests tonight on the rails to see how stable they are. What do you think of my theory?

By all means try it. I find the stock cooling simply innadequate on these supplies, and if your reducing it all the way to 5V, it is certainly innadequate. I had to try a lot of fans before finding the optimal combo for the original TP's and they are a lot stouter than the stock units.

Dell_Axim · Jun 4, 2005

Antec's biggest problem is bad thermal design. (Antec, it seems that even a 16 year old Chinese chick knows more about thermal design than your "professional" thermal engineers.)
When I got my Antec, after running it without mods for a day to make sure that it's not defective out of the box, I used a fingernail to carefully peel back the warranty label so I can rewire it (actually, all I did was jumper between the 12v line and the + side of the fan connectors). For the Antecs with fan only connectors, it might be possible to just connect the + side of the fan only connector to the 12v pin of a regular molex. (Have not verified this.)

larva · Jun 4, 2005

I have spoken with a product development guy at Antec, they do not participate in the design of these supplies. It's all Channel-Well, and its not that the thermal solutions aren't engineered. They are engineered to allow a really low noise rating to be given to Antec to publish, all other considerations (besides cost) be damned.

I am fairly certain that connecting the + terminal of the fan only connector to 12V will harm the supply's fan controller circuitry. While I would need to further investigate to declare this fact, without more information, I would strongly counsel to assume this notion unsafe as opposed to safe.

Dell_Axim · Jun 4, 2005

I have spoken with a product development guy at Antec, they do no participate in the design of these supplies. It's all Channel-Well, and its not that the thermal solutions aren't engineered. They are engineered to allow a really low noise rating to be given to Antec to publish, all other considerations (besides cost) be damned.

I am fairly certain that connecting the + terminal of the fan only connector to 12V will harm the supply's fan controller circuitry. While I would need to further investigate to declare this fact, without more information, I would strongly counsel to assume this notion unsafe as opposed to safe.

The strange thing is that my Dell PSU is also OEMed by Channel Well, and the stock cooling is better than Antec's. (No "hot varnish" smell during operation without mods.) Maybe Dell is actually aware of the problem and requests a faster running fan.

The mod should be safe for at least my Antec because I've been running it with the jumper for more than a week. It got rid of the "hot varnish" smell, at least.

6800Ultra not enough power-PSU problem?

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