8800 GT Power Issues - Need Help!!

[arnav]

So, i bought a Cooler Master 500W PSU which has 2x12V rails with 16A each. I got my 8800 GT today and says that it requires 26A on the 12V rails.
Obviously my PSU does not have it.
My question is will the card still run. i know its a sort of a dumb question, but i was so excited when i got my card that when i read the requirement it shattered my dream of finally being able to play these new games. I don't know what else to do?

If anyone can point out any good deals on 500W PSU's that have 12V rails with 26 amps or more, i would be very thankful.

 

[angry hampster]

16x2=32.

Shouldn't be a problem.

 

[DSF]

That's 26A for the entire system, not for the card alone. Also, you don't need 26A per rail, they're specifying a power supply with the capacity to supply 26A overall on the 12V rails.

Edit: And as far as 16x2 = 32, it doesn't always work that way.

 

[arnav]

So am I good or not?

 

[BassBomb]

you are fine

 

[ManWithNoName]

Originally posted by: DSF
That's 26A for the entire system, not for the card alone. Also, you don't need 26A per rail, they're specifying a power supply with the capacity to supply 26A overall on the 12V rails.

Edit: And as far as 16x2 = 32, it doesn't always work that way.

You're absolutely correct.

Originally posted by: angry hampster
16x2=32.

Shouldn't be a problem.

You don't add the rails to get the sustained/continuous amperage on the combined +12v rails. You take the total wattage of both +12v rails and divide by 12. Using my 620w Enermax as an example, I have two +12v rails which are 22a each. My sustained/continuous amperage is not 44a.

I have this....

432w divided by 12v = 36a (combined +12v rails)

So without knowing the wattage from both rails on his power supply all we can do is make a rough guess-timate. He could have anywhere from 23a-30a. So if he's only pulling 23a then it could be a toss-up n how well it will work.

Arnav,

What is the specific Cooler Master PSU Model # you have?

 

[arnav]

Cooler Master eXtreme Power 500W
Model # RP-500-PCAR Link to the exact PSU i bought

thank god u brought it up, i was this | | close to putting the card in.
phew!!

thanks

 

[spittledip]

Your psu puts out 27 amps for the 12v combined. The 5v and 3.3 put out 20 amps each (100 watts and 66 watts). 166 minus 500 = 334 watts left over for the 12v. 334 divided by 12 equals 27.8 amps. You should be good to go with that psu.. although it will be cutting it close.

Anyone have a problem with my figuring? Are there factors being left out, or is it all good?

edit: link to info http://www.coolermaster.com/up.../file1192532143531.pdf

 

[myocardia]

Originally posted by: spittledip
Anyone have a problem with my figuring? Are there factors being left out, or is it all good?

You forgot to subtract the 25-30 watts for the -5v, -12v, and +5Vsb. Which means that it has a maximum +12v output capability of closer to 300-305 watts. That would be about exactly 25A of combined +12v, which sounds about right to me. It's probably not enough, but who knows, anything is possible.

 

[n7]

You'll be fine.

 

[spittledip]

Originally posted by: myocardia

Originally posted by: spittledip
Anyone have a problem with my figuring? Are there factors being left out, or is it all good?

You forgot to subtract the 25-30 watts for the -5v, -12v, and +5Vsb. Which means that it has a maximum +12v output capability of closer to 300-305 watts. That would be about exactly 25A of combined +12v, which sounds about right to me. It's probably not enough, but who knows, anything is possible.

Ah yes, i was wondering about those. Looks like it is cutting it too close. At least too close for my comfort.

 

[ManWithNoName]

Originally posted by: arnav
Cooler Master eXtreme Power 500W
Model # RP-500-PCAR Link to the exact PSU i bought

thank god u brought it up, i was this | | close to putting the card in.
phew!!

thanks

That's OK, "usually" the worst that could happen is your computer wouldn't start.

Originally posted by: myocardia

Originally posted by: spittledip
Anyone have a problem with my figuring? Are there factors being left out, or is it all good?

You forgot to subtract the 25-30 watts for the -5v, -12v, and +5Vsb. Which means that it has a maximum +12v output capability of closer to 300-305 watts. That would be about exactly 25A of combined +12v, which sounds about right to me. It's probably not enough, but who knows, anything is possible.

That's sounds just about right to me as well and I agree. It may work or it may not. He'll need to test it and see.

 

[arnav]

alrite i am going to test it out right now
and reply my findings later

fingers crossed.

 

[n7]

Originally posted by: myocardia

Originally posted by: spittledip
Anyone have a problem with my figuring? Are there factors being left out, or is it all good?

You forgot to subtract the 25-30 watts for the -5v, -12v, and +5Vsb. Which means that it has a maximum +12v output capability of closer to 300-305 watts. That would be about exactly 25A of combined +12v, which sounds about right to me. It's probably not enough, but who knows, anything is possible.

Heh, it's enough unless the PSU is specced wrong.

I've seen an 8800 GT on a quad core 8 GB system running off a 300W generic PSU with around 20A on the +12V rails.
Ideal, no.
But it seemed to work, at least for a while

There are few systems that need more than 350W these days.

 

[aldamon]

Originally posted by: arnav
Cooler Master eXtreme Power 500W
Model # RP-500-PCAR Link to the exact PSU i bought

thank god u brought it up, i was this | | close to putting the card in.
phew!!

thanks

Careful. That PSU is not really a 500W unit. It's a rebadged 400W SevenTeam. I used one with my file server, but that system only draws 150W under full load. My Q6600 @ 3.5 GHz system with an 8800GT draws in the neighborhood of 300W under load. You're not going to have much breathing room with the PSU but it should work. You might want to consider a better unit. You're really slumming it considering how good the rest of your components are.

 

[ManWithNoName]

Originally posted by: arnav
alrite i am going to test it out right now
and reply my findings later

fingers crossed.

How are you testing it out? If I were you I would use ATITool Artifact Tester and run it for an hour or two. Don't depend on gaming alone to find out if you're stable as some games won't stress the card or PSU at all. Good luck.

 

[ionoxx]

500W witll be MORe than enough by a long shot.

My old rig ran

Overclocked Opteron 165
6 Hard drives
2 Optical Drives
2 7800GTs
Audigy Platinum

All this on an Antec True Power 2.0 EPS12V 550W

You won't even be close to the limits. My new rig in my sig runs 375-400W full load. This is read from a Kill-a-watt meter.

 

[ManWithNoName]

Originally posted by: ionoxx
500W witll be MORe than enough by a long shot.

My old rig ran

Overclocked Opteron 165
6 Hard drives
2 Optical Drives
2 7800GTs
Audigy Platinum

All this on an Antec True Power 2.0 EPS12V 550W

You won't even be close to the limits. My new rig in my sig runs 375-400W full load. This is read from a Kill-a-watt meter.

It ain't the wattage. It's more so the +12v rail amps and the quality of build.

 

[arnav]

ok
after I installed the card, the computer booted absolutely fine.
I played some of my favorite Halo, then I installed NFS Pro Street.
After about 15 or 20 mins, my screen went black and everything else froze. I had to hit the reset button to get out of it.
Either its because I set all the settings to high or its the card itself.

What setting should i put in the game to get ideal performance. Should I have VSYNC on?

 

[BlueAcolyte]

Well, I would guess that your PSU simply isn't up to the task if it dies while doing some light gaming. Get a better one.

 

[BassBomb]

check your temps too 8800GT can get toasty

 

[arnav]

My 512 MB 8800 GT idles around 50C and my quad cores idle around 35C
Under load the GT goes around 85C - 90C and quads are around 80C

 

[Narse]

Originally posted by: arnav
ok
after I installed the card, the computer booted absolutely fine.
I played some of my favorite Halo, then I installed NFS Pro Street.
After about 15 or 20 mins, my screen went black and everything else froze. I had to hit the reset button to get out of it.
Either its because I set all the settings to high or its the card itself.

What setting should i put in the game to get ideal performance. Should I have VSYNC on?

Sounds like heat to me, if it was the PSU it would most likely just reboot as soon as the game started, make sure you have plenty of venilation in your case, and if you have to use ntune to up your fan speeds to 100% and see if that helps.

 

[arnav]

if I change my fan speed using either ntune or rivatuner to 100% would it burn my card or stress it under game play?

Also, what should be good temps for the 8800GT 512mb (idle temps and load temps)?

 

[arnav]

now i my temps at idle are 43C and under load the temp is around 59C maybe
i think i am fine.

Thanks for all the help guys.

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