Amp Requirements for Video Cards

[saltorio]

I'm confused regarding the amp requirements I'm reading about all over for video cards. What I've read, is that many newer card require a PSU that can supply >20A on the +12V rail. But does this mean on a single rail, or overall for all +12V rails the PSU has (some have more than one)?

In my system which I built in January 2007, I have an Antec SmartPower v2.0 500W. According to it's published specs, it has 2 +12V rails, one at 17A, and the other at 19A. That would make for a total 36A on the pair of rails.

I ask because I've been having problems with my video in World of Warcraft for some time. I was getting the odd artifact here and there, but it has gotten worse lately, so much so that I had to downclock my Sapphire Radeon X1900XT 256MB (to note: it's always been run at default settings). Even there, I still get the odd artifact, though haven't experienced any more crashing.

Looking for info, I came across a post on the Sapphire forums where amperage of the +12V rail was mentioned. I'm wondering if my PSU isn't up to spec to drive the card (though I bought both at the same time), and that's causing the issue, or whether it's more likely a problem with the card itself.

 

[mpilchfamily]

The Antec SP2s are know to have problems. Chances are the PSU is on its way out. At most that PSU is only able to output about 24A max on the combined 12v rails. You don't go adding the rails up. The rating per rail are just that. It the max amount of power each rail is rated to safely carry. the actual amount threw each rail will very but will not exceed the PSUs actual power output to the combined rails. The card requirements you've read about are recommendations for the total system running that card and not just the card. Now since your getting artifacts that leads me to think that the Video RAM is going bad or the card is overheating. When was the last time you blew out the cooler on the card? If there is allot of dust built up in it then is won't be able to cool properly. It may be in your best interest to get a new PSU. Like i said the SP2 is known for its short comings. Brand new the PSU has plenty of power but over time its not able to maintain a heavy load as well as it once could. The SP2s are not well know for serving 2 years of use. Many tend to go bad after about 18 months.

 

[saltorio]

18 months. That's about right.

I cleaned the video card a few months back as best I could, but didn't have compressed air at the time. Yesterday I bought some, and spent a good hour blowing out the entire system, taking the vidcard out and focusing on it specifically. I have had overheating issues on the Radeon (leading me to to clean the system out the first time, and install ATI Tray Tools to bump up the fan speeds). Problems seem to occur more when the vidcard hits 70°C or so (at which point the fan is currently running at 100%). This happens most when flying around in WoW.

The artifacts are usually polygons that stretch in a straight line to infinity. It seems to happen most off trees and player models, and at times can be seen all over the place (whereas before they would happen extremely rarely).

So would I be better getting a PSU where there is one big +12V rail (such as the Corsair 550vx with 1x 41amp), or a PSU with multiple +12V rails (such as the Corsair 520hx, with 3x 18amp)? Ideally, I may want to upgrade to a GeForce 8800GT or 9600GT in the future, so I'd want something that could handle that.

And is it likely my vidcard is fried to some degree? I guess I'd determine that with a new PSU?

 

[MarcVenice]

One rail vs multiple rails is a moot point. Both of those corsairs would be fine, and the 520hx is in fact a single 12v rail design, although the manual sais different. Long story, but it's a single 12v rail PSU.

Here's a cheap 550vx: http://www.buy.com/retail/sear...e&display=col&dclksa=1

I'm not saying a new PSU is going to solve your problems btw. It might very well be that your 1900xt is broken. The smartpower 2.0 is susceptable to bad caps like mentioned though, so it 'could' solve your problems.

 

[saltorio]

Yeah, I know you can't guarantee the PSU will fix the problem. I have a good feeling the vidcard is toast, though I'd assume I'll need a new PSU no matter what, since a newer vidcard will require a better PSU anyways.

Just for reference, here are some images of the artifacts I've been seeing in WoW:

World of Warcraft - Visual Artifact Image 1
World of Warcraft - Visual Artifact Image 2
World of Warcraft - Visual Artifact Image 3

And while playing today, I've for the first time seen some odd text artifacts in the chat frame, as shown here:

World of Warcraft - Text Artifact Image 1
World of Warcraft - Text Artifact Image 2
World of Warcraft - Text Artifact Image 3

It's the appearance of these text artifacts, despite the vidcard being downclocked (to 459 core, 549 memory) that has me thinking the card is shot too.

 

[saltorio]

Just as a follow-up:

I went out and bought a new PSU (Corsair 520HX), which I installed into my system. Booted up and reset the Radeon X1900XT to it's default speeds (it had been downclocked as an attempted fix), then ran WoW... No change. Still had artifacts, just as many as with the Antec PSU.

So it looks like the PSU not giving enough amps for the card has damaged the card in some way.

So after bringing the GeForce 8600GT I had also bought back (stupid salesman told me it would be at least as powerful as my old Radeon... stupid me for not doing the research first to know he was full of crap), I picked up a lovely new EVGA e-Geforce 9600 GT Superclocked. It's wonderful. No artifacts, and a solid 60fps even with FSAA enabled.

So the morale of the story is, make sure you have a PSU that can consistently provide enough amps to the vidcard throughout it's life, or your vidcard can get damaged just as if you had OCed it too much.

 

[MarcVenice]

That's not quite the morale of the story. The ripple or noise of the PSU might have killed the card, although I could also be wrong in that statement. Your cards not getting enough amps won't kill it either though. It's more like the card just died a 'natural' death, because of it's own faults, like getting to hot or something.

 

[WavingBlue75]

PSU not pumping enough power or not providing consistent power is just 1 possibility. Lots of other things can go wrong with electronics.

 

[saltorio]

True enough.

I just would never have thought that electornics not getting enough power could cause long-term damage of any kind. I would've thought it would simply have caused errors and other short-term problems during use, but when sufficient power was given all would be well. Shows how little I know about electronics.

The Radeon was only 14 months old (I bought it new in Jan. 2007). I know electronics can fail at any time, but it's not like it was that old.