Dual Power Supplies?

[rjbudz]

Dual Powert Supplies?

First, my computer:

ASUS M3N-HT Deluxe/HDMI Motherboard
Phenom QUAD Processor
EVGA GeForce 9800GT (2x in SLI) Video
Fatality Titanium PRO Sound
4 Gigs RAM
DLink Wireless Network Card
1 SATA 320 gig HDD
1 SATA Lightscribe DVD
Big Antec case

The primary purpose for this system, as if you can’t tell, is gaming.

I recently added a Coolmax CPU sink (with big ol’ dual fans). Shortly afterward my 850 watt power supply up & died. The system just won’t start. If I toggle the IO switch, it will give me a quick bit of juice (fan whirls and lights up) then nothing.

I figure the PS just couldn’t take the load (does that sound about right?)

Anyway, I went shopping for a 1000 watt PS. I can’t see spending $250+ for a power supply if I can avoid it. So here’s my idea. I figure there must be a flaw in it, as I’ve not heard of anyone else doing it:

Why can’t I hook up two 850 power supplies? I connect the motherboard (with the CPU and mega fans) and the case cooling fans to one, then everything else to the other.

The only drawback I can see is the possibility of one failing, leaving the other one live. But even then since the equipment “pulls”, either one quitting would prevent the other from outputting power, right?

It’s a given that two 850s probably cost as much as the 1000 watt anyway, wouldn’t it be more efficient as far as the computer is concerned? Two power supplies will never run anywhere near their max capacity, so should be quieter and cooler. Since none of the equipment will be trying to suck up more power that is available, everyone will be happy!

And just think of the modded cases you can make with dual power supplies.

So….

Am I missing something?

[Lord Orwell]

unplug the power supply and let the system sit for about 5 minutes or so.

As for hooking up two power supplies, my system has two in it. I posted a youtube video with directions on how i did it. Link at end of this post.
As for the wattage, 850 should have been plenty. I'm currently running a phenom, 4 gb ram, 1 hard drive, lightscribe burner, And a 12 volt flatscreen powered directly off the power supply, and usb speakers, with 420 watts.
My system with two power supplies was still only a little under 700 watts but i had all this hardware:
athalon x2 processor (same wattage as phenom)
4gb ram
8600 video card (overclocked 30&#37
FIVE hard drives
Lightscribe burner
Combo radio and analog tuner card
Combo Digital and Analog tuner
TFT display
USB Bluetooth
USB Wireless G
Multi-card reader
USB Speakers.

Based on this, you can see that you need some serious hardware to need more than 800 watts.

You can also test your power supply by jumping a paper clip between the green wire and an adjoining black wire and plugging a dvd player into one of the connectors then plugging it in to the wall. Assuming the fan is powered from the supply it will start spinning and the dvd should spin up. DO NOT DO THIS WITHOUT SOMETHING CONNECTED TO THE SUPPLY!

http://www.youtube.com/watch?v=BUMy_2bw7gA
no sound due to a copyright claim on 5 seconds of sound i used in the credits. I am currently disputing it under fair use.

And here's the final work mounted on the back of the system.
http://www.youtube.com/watch?v=9ayBvi7zzds
start watching it at about a minute thirty seconds.

[rjbudz]

Looks like I found the right person to answer my questions. Rather, you found me. Thank you.

I've not had the chance to watch the vids in full, but I wanted to get back to you quickly. Here are a couple questions:

1) The green wire (I assume this is the 24 pin group that plugs into the moboard) has a black wire on either side of it (in the same 12 pin "row"). Which is the right one to use?

2) I'm pretty convinced the power supply is dead as I've had the power supply off for days and no difference. The power supply is about 2 months old. Could it have been defective? The reason I ask is because someone told me that I may have been maxing the power supply with my setup.

3) You said you have 2 power supplies on your system. What are the ratings for each one and to which do you have each component plugged? I'm replacing the 850 and have a brand new 400 sitting around here somewhere. If I can use the 400 rather than buying another 850, that'd be great, but I don't want to under-power anything. How can I tell what the requirements are for the specific components, such as: Do my 9800GTs need more than 400 watts to run?

Thanks again.

[Lord Orwell]

Looks like I found the right person to answer my questions. Rather, you found me. Thank you.

I've not had the chance to watch the vids in full, but I wanted to get back to you quickly. Here are a couple questions:

1) The green wire (I assume this is the 24 pin group that plugs into the moboard) has a black wire on either side of it (in the same 12 pin "row"). Which is the right one to use?

2) I'm pretty convinced the power supply is dead as I've had the power supply off for days and no difference. The power supply is about 2 months old. Could it have been defective? The reason I ask is because someone told me that I may have been maxing the power supply with my setup.

3) You said you have 2 power supplies on your system. What are the ratings for each one and to which do you have each component plugged? I'm replacing the 850 and have a brand new 400 sitting around here somewhere. If I can use the 400 rather than buying another 850, that'd be great, but I don't want to under-power anything. How can I tell what the requirements are for the specific components, such as: Do my 9800GTs need more than 400 watts to run?

Thanks again.

1. Either one will work. The black wires are all ground wires.
2. Yes. To see the power requirement, i suggest you use an online power consumption calculator such as http://www.thermaltake.outervision.com/Power, although i would add a buffer to your results. And don't assume the suppy is dead until you test it. It could easily be your board, you know.
3. For power consumption, see #2. Supposedly my system only needed 400watts with everything running, and it did in fact boot off one power supply, however there is the issue of every hard drive spinning up at once, and it would sometimes not see all five of them. The 2nd power supply i installed is out of an ibm and says "not to exceed 185 watts" and i am powering 3 of the hard drives and the dvd burner off of it. Everything else is powered from the other power supply. So total power available for the system is 185 + 420 = 605 watts.

If you have $45 to spare, check this ebay auction out:
http://cgi.ebay.com/ws/eBayISAPI.dll...m=170312142888
edit: and here's a new listing for the same price
http://cgi.ebay.com/BUMP-UP-MY-POWER...3286.m20.l1116

Finally, the easiest way to tell if you are underpowering anything is to choose the "restart" option in windows. After the supply has warmed up it will usually not have enough amperage to redo a post.

[Jenner]

Yes, the power supply is most likely dead. Probably due to one of it's internal components overheating and failing. It's a common problem. I've seen bigger PSUs die in similar fashions. 850 Watts is way more than you need for that system. Just a rough look I'd say you're using about 550 Watts with your hardware at most.

It could have failed because you were drawing too much power from one of your rails as well. Remember, a 2-rail 850W power supply may be split 450W on rail 1 and 400W on the other. If you overload one, it will die on you. Also, those rails are broken down by the voltage of each line. The 3.3V line may only be rated at 92W, the 5V at 150W, the 12V at 408W...

Also, the "rating" of a PSU is something subjective to marketing. Just because a PSU can take a draw of 850W for 3 seconds, doesn't mean it can take it continuously. The problem with PSU manufacturers is they are marketing to the "gaming" crowd who have deep pockets and think just because the numbers are bigger, it must be a better piece of equipment so they "fudge" the numbers. The best way around this is to make sure the PSU is "UL Certified" which means that the testing procedures for it has been certified as valid and unbiased by Underwriters Laboratories and chances are, there's little marketing influance in the numbers.

What brand PSU did you have?

Dual PSUs is is typically only done in a server as a failsafe in case one fails. If wired in parallel, you could increase the maximum load per rail, but you really wouldn't be gaining anything except bragging rights.

[Lord Orwell]

Underwriter's laboratory is another good one. Also the backwards UR, which i forget what it stands for, but it's european certification.

As for split rails, this is actually a rare find to find a power supply with the rails actually isolated. It's supposed to give clean power but the isolation circuitry is expensive and to keep prices down they usually just include a couple of diodes to stop back current but they are still interconnected. There's an interesting wikipedia article on it.

[rjbudz]

I have an A-Power AK Series 850. Just like the ones in the auctions except 850 instead of 750! I bought it via Geeks.com for $49.95

I tried the paper clip trick with the power supply because the thought of my motherboard being fried freaked me out. Guess what? Power supply works just fine. (Cool trick!) I re-hooked it up to the motherboard/system, plugged it in and made sure the IO switch on the PS was on. Light came on the board, but it didn't start. More freaking out.

Of course, then I remembered you need to push the button on the front of the case. It all works again.

What's up with that? Any idea what happened?

I'm sure the power supply did NOT work more than the instant after toggling the IO switch on the PS and pushing the case button. Even tried it out the next day and a few days later.

Assuming I can just pretend the last week never happened, I have another power supply (same one) on the way. Do I return the "defective" one or the replacement one? What I mean is: Is this likely to happen again with either of them?

Should I try out the Dual Power supply setup?

I realize responses will be opinions, but I'd like to know what you all think.

Thanks!

[Lord Orwell]

this crap just happens sometimes. It's why i was pretty sure your power supply worked. A power supply is ALWAYS on when it is hooked to a pc. It's just a matter of how much it is on. This is why i suggested rehooking it up after it was unplugged. Your bios is software and it keeps data in memory from capacitors for up to a few minutes even after you have unplugged it from the wall. It's also possible that your power supply has a heat-activated breaker switch in it.

[rjbudz]

The heat thing may be it.

It was the first time I had sealed the case since putting the mega cooler on. I'd have thought the Coolmax would have evacuated more air from the case rather than add to it. It may be time to slap an extra case fan outside the power supply vent.

[Lord Orwell]

The heat thing may be it.

It was the first time I had sealed the case since putting the mega cooler on. I'd have thought the Coolmax would have evacuated more air from the case rather than add to it. It may be time to slap an extra case fan outside the power supply vent.

check the direction of air flow. also you can't ever have too much air flow in a case. Mine has a 120mm fan i installed custom into the side panel, blowing fresh air into the case and pretty much above the processor; and the 2nd power supply i added i replaced the fan with a 6000rpm cpu fan then hooked it to the motherboard's case fan connector. If it gets too hot in there, it spins up, sucking air from the case. Kinda loud though.
This is one of the reasons i'm eyeballing the hd4870 radeon card for my htpc. It exhausts heat outside the case.

[Lord Orwell]

just as a followup, i won the claim against my video, and the sound is back.