Power Supply and video card

alasz11 · 07-19-2007, 05:30 PM

Hi,

I just bought an Nvidia 7900GS and discovered that my computer's power supply isn't good enough for it. I received a message on startup saying it is not getting enough power and as such will scale back its quality so that it doesn't damage the system. The card requires 450 Watts and 22 amps on the 12 volt (not really sure what that means, and I might have mangled exactly what it is, but hopefully you get the idea). My computer's power supply is 450 Watts and 15 amps on the 12 volt. Anyway, I played Battlefield 2 at full settings with 2x anti-aliasing and it got terrible FPS, meaning that the card seriously scaled back its performance.

I had a brainstorm to try to connect the additional power wires that came with the card to another power slot that I don't use in the computer (thinking if I took the power from the floppy and rerouted it to the card I'd be ok). I opened up the computer and found that there was an extra power chord dangling inside, unused. So I just hooked it up to the video card and turned the computer back on. Sure enough, no message saying the card wasn't getting enough power. Good sign. I tried BF2 again and it ran much, much smoother.

However, it does slow up from time to time, which I don't think should happen with this card. In addition, World of Warcraft, a game released long ago, isn't getting the best FPS either, which concerns me (my average laptop should not be outperforming my desktop with a 7900GS).

So, I have a few questions for you:
[1] Was my idea a good one? Is everything ok with me just hooking up that spare power chord to the video card's supplemental power slot? Does that conceptually sound correct?
[2] How can I check how much power my card is getting and using? I'd like to be able to confirm that it's getting more power now and make sure I got rid of the problem, not just the error message.
[3] I'm planning on doing the system tools stuff (defrag etc) to try to get some performance back. This whole thing is actually for my brother, who, while I was away at college, accumulated a ton of crap on my old desktop. I'm thinking a total wipe and HD format might be in order, since my best estimate would be that the card is getting enough power but the system itself is just chugging along because of all the junk.

Specs:
Alienware purchased in early 2005
Pentium 4 w/ HT, 3ghz,
1 gb RAM
Windows XP home SP-2

Thanks in advance!

**oscaryu1** · 07-19-2007, 05:59 PM

If it requires 22Amps on the 12+ Rail than I can tell you right now its still downclocking.

http://cgi.ebay.com/600-Watt-ATX-Com...QQcmdZViewItem

^ I have that in my E4300 and its runnin fine. Think its 24Amps... 600W too.

http://www.newegg.com/Product/Produc...82E16817170010

^ Probably better one

alasz11 · 07-19-2007, 09:13 PM

Thanks

Now, what would I need to do to make sure those power supplies are in fact compatible? I know physical space is one thing I need to check.

Perhaps it would be better if I posted up my current power supply and somebody could tell if one of the ones posted here would be able to take its place? Of course, I don't know how to check what my current power supply is, so I'd need to know that, first.

chupacabra · 07-19-2007, 09:17 PM

Is compatible since you case is mid-tower atx (that's what alienware standard on cases), but if i were you i would buy a quality unit not just one cheap

alasz11 · 07-19-2007, 09:26 PM

Well, what would you recommend for quality? Keep in mind all I really want is to be able to fully use this video card.

Also, how hard is the install on these things? Seems like a lot of wires run from it.

And finally, anyone have an answer to my second question above? I'd like to be able to know just how far it's underclocking.

chupacabra · 07-19-2007, 10:18 PM

Quote:

Originally Posted by alasz11

Well, what would you recommend for quality? Keep in mind all I really want is to be able to fully use this video card.

Also, how hard is the install on these things? Seems like a lot of wires run from it.

And finally, anyone have an answer to my second question above? I'd like to be able to know just how far it's underclocking.

http://www.tigerdirect.com/applicati...4307&CatId=106

Isn't that hard just that you have to have good logic to know where to connect each one.

Probably around half if not more

alasz11 · 07-19-2007, 10:46 PM

question about that card from tiger direct though, it has two different +12V spots, under one is 16A and under the other 18A... does that mean that you add them up (34A on the +12V?). Also, would that mean there are two different +12V slots, and I would need to connect both of them (which wouldn't be a big deal, considering the card has the extra spot).

chupacabra · 07-20-2007, 12:23 AM

Quote:

Originally Posted by alasz11

question about that card from tiger direct though, it has two different +12V spots, under one is 16A and under the other 18A... does that mean that you add them up (34A on the +12V?). Also, would that mean there are two different +12V slots, and I would need to connect both of them (which wouldn't be a big deal, considering the card has the extra spot).

Correct me if i'm wrong but, it sucks the amps on one rail and if isn't enough it "sucks" the rest from the 2 or 3 or 4 rail 12@v, the 2 pci-e connecters are for sli, 2 nvidia cards working as "one" using a bridge and software.

**ceewi1** · 07-20-2007, 01:01 PM

For an ATX complaint design such as that Ultra, +12V2 powers the CPU, while +12V1 powers everything else. What the video card requirements are looking for is the total +12V amperage. If you look at the label on the PSU, underneath the two individual +12V ratings you'll see a wattage number - 384W. This is the total power that can be provided by the +12V rails. Divide this by 12 to get the total +12V amperage (32A, in this case). As these calculations imply, this PSU is more than sufficient for a 7900GS.

Quote:

[1] Was my idea a good one? Is everything ok with me just hooking up that spare power chord to the video card's supplemental power slot? Does that conceptually sound correct?

Yes, that connection will need to be plugged in, or else you will invariably get the error message you described.

Quote:

[2] How can I check how much power my card is getting and using? I'd like to be able to confirm that it's getting more power now and make sure I got rid of the problem, not just the error message.

Short of getting your hands on some fairly sophisticated test equipment, there's no way of telling how much power a video card is using or receiving.

Quote:

[3] I'm planning on doing the system tools stuff (defrag etc) to try to get some performance back. This whole thing is actually for my brother, who, while I was away at college, accumulated a ton of crap on my old desktop. I'm thinking a total wipe and HD format might be in order, since my best estimate would be that the card is getting enough power but the system itself is just chugging along because of all the junk.

That sounds like a good idea. Make sure that the graphics driver is correctly installed as well.

The Ultra X-Finity is a good choice. You might want to to take a look at my entire list of recommendations: ceewi1's PSU Recommendations

alasz11 · 07-27-2007, 03:29 AM

I got the power supply and hooked it up with only minimal problems. Everything runs great now, so thanks for all the excellent advice!

One last question. The power supply has all these extra cables that don't hook up to anything (I imagine they're for multiple hard drives, CD-ROM's, etc). They're kind of in the way in the case. What do you guys do with extra cables that just run the risk of hanging against the fan at some point? Cut them? Tie them off?

Thanks

07-19-2007, 05:30 PM	#1 (permalink)
alasz11 New Member Join Date: Jul 2007 Posts: 7	Power Supply and video card Hi, I just bought an Nvidia 7900GS and discovered that my computer's power supply isn't good enough for it. I received a message on startup saying it is not getting enough power and as such will scale back its quality so that it doesn't damage the system. The card requires 450 Watts and 22 amps on the 12 volt (not really sure what that means, and I might have mangled exactly what it is, but hopefully you get the idea). My computer's power supply is 450 Watts and 15 amps on the 12 volt. Anyway, I played Battlefield 2 at full settings with 2x anti-aliasing and it got terrible FPS, meaning that the card seriously scaled back its performance. I had a brainstorm to try to connect the additional power wires that came with the card to another power slot that I don't use in the computer (thinking if I took the power from the floppy and rerouted it to the card I'd be ok). I opened up the computer and found that there was an extra power chord dangling inside, unused. So I just hooked it up to the video card and turned the computer back on. Sure enough, no message saying the card wasn't getting enough power. Good sign. I tried BF2 again and it ran much, much smoother. However, it does slow up from time to time, which I don't think should happen with this card. In addition, World of Warcraft, a game released long ago, isn't getting the best FPS either, which concerns me (my average laptop should not be outperforming my desktop with a 7900GS). So, I have a few questions for you: [1] Was my idea a good one? Is everything ok with me just hooking up that spare power chord to the video card's supplemental power slot? Does that conceptually sound correct? [2] How can I check how much power my card is getting and using? I'd like to be able to confirm that it's getting more power now and make sure I got rid of the problem, not just the error message. [3] I'm planning on doing the system tools stuff (defrag etc) to try to get some performance back. This whole thing is actually for my brother, who, while I was away at college, accumulated a ton of crap on my old desktop. I'm thinking a total wipe and HD format might be in order, since my best estimate would be that the card is getting enough power but the system itself is just chugging along because of all the junk. Specs: Alienware purchased in early 2005 Pentium 4 w/ HT, 3ghz, 1 gb RAM Windows XP home SP-2 Thanks in advance!

07-19-2007, 05:59 PM	#2 (permalink)
oscaryu1 Moderator Join Date: Apr 2007 Location: Houston, Texas Age: 13 Posts: 10,352	If it requires 22Amps on the 12+ Rail than I can tell you right now its still downclocking. http://cgi.ebay.com/600-Watt-ATX-Com...QQcmdZViewItem ^ I have that in my E4300 and its runnin fine. Think its 24Amps... 600W too. http://www.newegg.com/Product/Produc...82E16817170010 ^ Probably better one __________________ Core 2 Duo E2140 1.6GHz @ 3.04GHz GA-P31-DS3L pqi Turbo CL4 DDR2-800 2GB Sapphire HD3850 256MB Sony Writemaster DVD Burner EIDE Seagate Barracuda 80GB 7200.9 8MB SATII

07-19-2007, 09:17 PM	#4 (permalink)
chupacabra Diamond Member Join Date: Mar 2007 Posts: 1,923	Is compatible since you case is mid-tower atx (that's what alienware standard on cases), but if i were you i would buy a quality unit not just one cheap __________________ My Rig e7200 @ 2.53ghz 4GB G.skill pc6400 Seagate hdd 250gb Gigabyte P35 DS3L Sapphire 4850 Corsair 750 watts Raidmax Smilodon

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07-19-2007, 09:13 PM	#3 (permalink)
alasz11 New Member Join Date: Jul 2007 Posts: 7	Thanks Now, what would I need to do to make sure those power supplies are in fact compatible? I know physical space is one thing I need to check. Perhaps it would be better if I posted up my current power supply and somebody could tell if one of the ones posted here would be able to take its place? Of course, I don't know how to check what my current power supply is, so I'd need to know that, first.

07-19-2007, 09:26 PM	#5 (permalink)
alasz11 New Member Join Date: Jul 2007 Posts: 7	Well, what would you recommend for quality? Keep in mind all I really want is to be able to fully use this video card. Also, how hard is the install on these things? Seems like a lot of wires run from it. And finally, anyone have an answer to my second question above? I'd like to be able to know just how far it's underclocking.

07-19-2007, 10:46 PM	#7 (permalink)
alasz11 New Member Join Date: Jul 2007 Posts: 7	question about that card from tiger direct though, it has two different +12V spots, under one is 16A and under the other 18A... does that mean that you add them up (34A on the +12V?). Also, would that mean there are two different +12V slots, and I would need to connect both of them (which wouldn't be a big deal, considering the card has the extra spot).

07-27-2007, 03:29 AM	#10 (permalink)
alasz11 New Member Join Date: Jul 2007 Posts: 7	I got the power supply and hooked it up with only minimal problems. Everything runs great now, so thanks for all the excellent advice! One last question. The power supply has all these extra cables that don't hook up to anything (I imagine they're for multiple hard drives, CD-ROM's, etc). They're kind of in the way in the case. What do you guys do with extra cables that just run the risk of hanging against the fan at some point? Cut them? Tie them off? Thanks