EVGA Claims Seasonic S12 500 Insufficient For 7900GT

GHz · Post by **GHz** » Fri May 19, 2006 6:38 pm

Hey guys,

I recently bought an EVGA 7900GT KO from Newegg. Unfortunately, after 2 days the video card started acting up. Games and 3D applications would have graphical glitches/artifacts, and exiting those applications caused my monitor to flicker (intermittant signal loss).

I contacted EVGA and they cross-shipped a replacement to me. After 2 days of problem-free operation, the same thing happened. I called EVGA and explained the situation, and the CSR I spoke with immediately blamed my computer, claiming my Seasonic S12 500 isn't enough to power even a single 7900GT (despite its SLI certification). Of course I told the CSR he's wrong, but he was very insistant. He even went on to claim that every 7900GT they got back from RMA was just fine... the customer's equipment was to blame. You can view the thread I created on EVGA's forums here:

http://www.evga.com/community/messagebo ... C_ID=15274

I'm not trying to flame EVGA (even though the CSR's behavior was inappropriate); I just want to know if there is any merit to his claim. I seriously doubt that a 90nm low-power GPU (compared to 7800/7900GTX and X1800/1900XTX) is overpowering my PSU. This doesn't make any sense as I don't see any signs of stress from my PSU when the video card starts flaking out. Besides, if it were the PSU, why would the video card work just fine for 2 days and THEN crap out? Can I prove EVGA wrong?

My apologies if this is in the wrong forum/category. I posted here because this is mostly a power supply question/issue.

TIA!

EDIT: Oops, forgot my system specs:

AMD Athlon64 X2 4200+ @ 1.25V (53W TDP@stock)
Epox 9NPA+ Nforce4 Ultra
NEC ND-3540A DVD-RW
1GB (2x512MB) OCZ Platinum Rev. 2 PC3200
Samsung P120 200GB SATA3.0G
EVGA 7900GT KO (500/1500 stock)
Seasonic S12 500 Rev. A2 (+12V1 17A, +12V2 16A)

GHz · Post by **GHz** » Fri May 19, 2006 7:50 pm

I may have already proven my point. I just ran some tests of my own and measured both voltage (using a DMM) and peak current (using P3 Kill-A-Watt meter). Here's the results:

IDLE - 101W AC, 12.09V
RTHDRIBL - 155W, 12.09V
FEAR - 152W, 12.10V
FEAR TEST - 155W, 12.10V
3DMARK06 HDR1 Canyon Flight - 159W, 12.10V
3DMARK06 HDR2 Deep Freeze - 165W, 12.10V

So the maximum that this computer will pull when running a 3D application is 165W AC. At this load, the PSU was exhibiting no increase in fan speed and only luke-warm air was coming out of the exhaust. Measured +12V rail at 12.10 volts is well within spec and hardly changed at all between idle and load conditions.

If we assume the PSU is at least 80% efficient (and this is a pretty low estimate), then thats 165*0.8 = 132W DC. Just for the sake of argument, let's say all 132W DC is coming off a single 12V rail, that's only 132/12 = 11A! Now unless my math is wrong, this proves that EVGA's claim is total BS! Can anyone verify?

nici · Post by **nici** » Fri May 19, 2006 8:24 pm

According to the SPCR review the effiency of your PSU is 85% at 177W AC and still 83% at 109W so lets say its 84,4% at 165W wich is
139.4W DC.

For the hell of it lets say the whole 165W is DC and comes from one 12V line, its still just 13.75A.. So yes the PSU is definately enough.

Btw them new components seem pretty efficient, my system with a 3700+ and a x800GTO and a laptop HDD draws 175W AC at load.. The Phantom is about 80% efficient at that load according to the SPCR review.

GHz · Post by **GHz** » Fri May 19, 2006 8:38 pm

I was pretty shocked myself. This new video card that supposedly requires 22A uses less power than my "old" ATI X800XL. I really don't want the hassle of going through multiple RMAs just to get a good card... which really sucks because it's a wonderful card when it works. It performs well and uses little power. My only other option is an ATI X1800XT, but that card runs hotter and uses twice the power (according to xbit labs):

http://www.xbitlabs.com/articles/video/ ... 0gt_4.html

I have to make my decision soon because my 30 day return with Newegg will run out

I wish I could get an extension from them while I haggle with EVGA to get a working unit.

JazzJackRabbit · Post by **JazzJackRabbit** » Fri May 19, 2006 9:10 pm

GHz wrote:http://www.evga.com/community/messagebo ... C_ID=15274

That thread is really amusing

Anyway, from what I gather reading several posts in that thread several people actually know what they are doing and it appears there are problems with the stock evga overclocking.

Most likely your system is fine and it's the card acting up. Just to make sure I would advise you to try it in a different system though.

I don't think you can prove customer service wrong. Most customer service representatives don't have a clue or are being instructed to lie to customer. I seriously doubt you'll get anywhere. Try calling different time and get a different rep so that you could exchange the card, just don't mention it's your third (or whatever) RMA if you can avoid it.

If I were you I'd either try to downclock the card and see if artefacts disappear or simply return it to newegg.

frostedflakes · Post by **frostedflakes** » Fri May 19, 2006 9:54 pm

I think it is pretty obvious that your power supply is more than sufficient for that video card. Under normal circumstances, I'd tend to think that if three cards were all exhibiting the same problem, you're system would be to blame, but from the sounds of it others are having problems as well. Sounds like somebody, either nVidia or eVGA, screwed up big time. Good luck, hopefully you get everything worked out.

P.S. Looks like some of the people in that thread need a wake up call, the graphics card and power supply companies have them all brainwashed to think they need 600w power supplies for their non-SLI computer. Maybe we should pitch in and buy them wattmeters.

GHz · Post by **GHz** » Fri May 19, 2006 9:59 pm

Well I guess it's the SPCR mindset I've learned here that makes me want to prove that you don't need a rediculous 600-700W power supply. According to Xbit Labs (see http://www.xbitlabs.com/articles/video/ ... 0gt_4.html), the 7900GT CO SC consumes a maximum of ~57W DC, which agrees with my findings.

burebista · Post by **burebista** » Fri May 19, 2006 10:08 pm

Those Superclocked versions of 7900GT(X) are defective (EVGA, XFX, maybe others too). We have a lot of users here with your problems. Maybe this thread is useful...

frostedflakes · Post by **frostedflakes** » Fri May 19, 2006 10:48 pm

So are the cores defective, or just overclocked too high? For what it's worth, my factory overclocked (520/1500) XFX hasn't given me any problems recently, although when I first got it I'd get reboots and other problems occasionally while gaming. At first I just assumed it was a bug with Oblivion, so I was just going to wait for a patch or newer drivers, but after a week or two it just stopped happening. Maybe the GPUs need to be burnt in or something, I really have no idea.

Big Pimp Daddy · Post by **Big Pimp Daddy** » Sat May 20, 2006 1:36 am

Yeah, my system (inc. xfx 7900GT stock speeds) is running completely stable with a generic 350W power supply, with an alleged 16A on the lone 12v rail.

jaganath · Post by **jaganath** » Sat May 20, 2006 1:38 am

Most customer service representatives don't have a clue or are being instructed to lie to customer.

This is very true IME (as someone who used to work as a CSR).

McBanjo · Post by **McBanjo** » Sat May 20, 2006 3:21 am

My Antec NeoHE 500W works just fine with stock-clocked eVGA 7900GT. Had some trouble with drivers, so it might be either drivers or overclock that messes things up. Try to clock it down to stock speed and check if that works

McBanjo · Post by **McBanjo** » Sat May 20, 2006 3:25 am

Hmm, if I get it correct in that evga-thread then it would be impossible to run their card since max current on a single rail is supposed to be 20A or are they consider the all rails with 12V to be 1 single rail?

TomZ · Post by **TomZ** » Sat May 20, 2006 9:27 am

GHz wrote:I was pretty shocked myself. This new video card that supposedly requires 22A uses less power than my "old" ATI X800XL. I really don't want the hassle of going through multiple RMAs just to get a good card... which really sucks because it's a wonderful card when it works. It performs well and uses little power. My only other option is an ATI X1800XT, but that card runs hotter and uses twice the power (according to xbit labs):

http://www.xbitlabs.com/articles/video/ ... 0gt_4.html

I have to make my decision soon because my 30 day return with Newegg will run out I wish I could get an extension from them while I haggle with EVGA to get a working unit.

If I were you, I would just RMA the card, and move on to a different model. Obviously something is screwed up, and even if you can manage to get something working now, additional problems could crop up later. Why mess with it? There are so many cards in the market.

One other thing, power is not just as simple as "watts." It is technically possible that there would be other more subtle compatibily problems besides the power supply being able to supply enough current. For example, maybe the eVGA card has large load fluctuations that are causing the PSU output voltage to droop. Who knows? Without a detailed technical analysis of you exact situation, I don't think you can fairly conclude that eVGA are wrong. I'm not saying this is "likely," just "possible."

GHz · Post by **GHz** » Sat May 20, 2006 12:46 pm

Tom,

I appreciate your input, and I know that the problem may not be simple. However, I think I can conclusively say that a *single* card does NOT require a 600+W power supply (which is what EVGA was suggesting). I very carefully monitored voltage and current under load and the figures you see are worst-case conditions... i.e. the current recorded are peak figures. Large load fluctuations would have been observed, as well as voltage droop (that was the purpose of monitoring the +12V line under load).

What's really sad about this is that many people have taken EVGA's misguided advice and spent a lot of money on these rediculous power supplies when it was never necessary. That's why I think it's necessary to have evidence that these "requirements" are total BS.

McBanjo · Post by **McBanjo** » Sat May 20, 2006 1:35 pm

My guess is that it's becourse of the A they recommend high W units since that's what people look for. You don't really find (atleast I don't think so) a 300W 2x18A on 12V rail units.
But it seems they are still in ATX 1.1 format since they should specify what A is needed on 1 of the 12V rails and then maby add in W as well

jaganath · Post by **jaganath** » Sun May 21, 2006 1:02 am

What's really sad about this is that many people have taken EVGA's misguided advice and spent a lot of money on these rediculous power supplies when it was never necessary. That's why I think it's necessary to have evidence that these "requirements" are total BS.

One would almost think that the video card and power supply companies are in cahoots, conspiring together to dupe people into buying ludicrously oversized PSU's....surely not

Entropicity · Post by **Entropicity** » Tue May 23, 2006 12:20 am

Could your problem be this?

http://www.evga.com/community/messagebo ... C_ID=14558

EVGA Claims Seasonic S12 500 Insufficient For 7900GT

EVGA Claims Seasonic S12 500 Insufficient For 7900GT

Re: EVGA Claims Seasonic S12 500 Insufficient For 7900GT