Check your amps! A harsh lesson learned.

BeardedGent

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Feb 23, 2013
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So, some of you might remember a small thread I made a couple of days ago about my GPU dying on me. Well, the replacement came in today. Now, I got a 9800GT with the intention of it being a temporary card to hold me over until I could afford a better one. My PSU was a year old and 650 watt. The 9800GT recommends 430, not to mention that it's what? Five or six years old?

The new card got here today, I put it in, hooked everything back up and powered on. Installed the latest drivers, temps looked great, I even loaded up WoW to see how it'd do under load. Well, around an hour and a half in the PC suddenly shuts down and will not turn back on. Plus, I could smell the distinct odor of burnt electronics. My PSU is fried. Why? The 9800GT requires 26 amps on the 12v+ rail. My PSU had 20. Now, I'm sitting with my fingers crossed that it didn't take anything with it since it shut itself off. It didn't shoot sparks or blow up, just shut down. Long story short, and a good lesson learned? Make sure your PSU can handle your GPU even if you're well over the watt requirements.
 
This is true, although I didn't consider it because it's just a year old. I'm just incredibly concerned about everything else now. If it took out anything else, I'd be left without a PC at all.
 


No, it wasn't age. It was under amped for that video card. It's not a known brand, I had it installed at a well respected and local repair shop. I'm going with an actual named brand now though and putting it in myself this time.
 

This is incorrect. The 9800 GT max TDP is 105 watts. At 12 volts, the maximum draw is 8.75 amps.

You had something else go wrong. What brand was this 650W power supply? It should have way more than 20 amps on the 12 volt rail.
 


Zuma. I'm looking at it. It says 650w max, 12v 1 and 2 at 20amps. Model number is ZU650W. Card on newegg does specify 26amps.
 


TDP is just the thermal dissipation

its should not stress out the the 20 amps on 12v = 240W and the cpu is usually on a separate rail in dual rail PSU's

msi9800gt_power.gif
 


I actually bookmarked that PSU right before posting here.
 


True that but TDP is overly safe sometimes 😛
 

Zuma is not a reliable brand. That's probably why it blew up on you, unfortunately.

As for the 26 amps.... you're reading Newegg wrong. That 26 amps is the minimum requirement for the POWER SUPPLY, not the card.

From the specs of the only 9800 GT on Newegg (http://www.newegg.com/Product/Product.aspx?Item=N82E16814130534)....

"Minimum of a 400 Watt power supply. (Minimum recommended power supply with +12 Volt current rating of 26 Amps.)"
 


That puts the blown PSU at 6 amps short (if it's even labeled correctly).
 

Look dude, your 9800 GT only draws 8.75 amps MAXIMUM. The newegg specs are saying you need a power supply that can push out at least 26 amps on the 12 volt rail. Your card can only consume 8.75 of those 26. You had a PSU that SHOULD have been able to push out much more than 26 amps, more like 50+. Your card did not draw too much power to blow up the PSU. The PSU died because it was a crappy brand or some other reason. But NOT because your 9800 GT drew 26 amps!
 


I realize the PSU is a PoS. I also realize that I read the description wrong. I am new to this so your hostility isn't needed. And, no, that PSU shouldn't be able to push that much. I'm betting it isn't even correct in what it does list. You can bet that I won't be going through that repair shop again. As I said, I'm doing it myself. Also, it did run my old 5770HD without issues since 2011. But, obviously it didn't have the same recommendations.
 
You have 2 12v rails 20a on 12v1 and 20a on 12v2 for a total of 40a (way more than 26 needed in the suggested PSU)

The CPU is on either 12v1 or 12v2 sometimes with the motherboard so has 20a all for itself

The GPU is on the other one with 20a for hdd, mb, fans and gpu
20-9 = 11 amps for everything else which is plenty