GTX 260 power question.

[mrwaffles]

I have a GTX 260 it says it needs minimum of 500W (36A on 12V rail). I have a Cooler Master Real Power Pro 850W that has 4x 12V at 18A and 2x 12V at 28A. The video card takes two 12V. So my question is is there enough amps to run the card fully? Does putting two 12V at 28A make the card's available power at 24V at 56A or is it still 12V at 28A?

Also what are the rails in the power supply?

Thanks,

Chris

 

[delluser1]

I have a GTX 260 it says it needs minimum of 500W (36A on 12V rail).

"It" doesn't need all that power, that's the recommendation for the "system" you wish to install it in.

 

[jsc]

DellUser1 is right. The 12 volt @36 amp is a minimum suggested power for, I think, the "average" or "typical" system - what ever that means.

A GTX260 by itself needs about 14 amps.

 

[mrwaffles]

So with a system of Q6600 2.4ghz quad core, 4gigs of ram, one harddrive, one cd drive, and the GTX260 is the power supply good enough to run it all fully? Sorry, I don't know anything about power.

 

[delluser1]

Your psu could probably run 3 of them without a problem.

 

[mrwaffles]

Alright. Thanks for all the help.

Chris

 

[mrwaffles]

What exactly is a rail? What's the difference when I hear people say a single powerful rail is better than numerous less powerful rails?

 

[delluser1]

Read this
http://www.jonnyguru.com/forums/showthread.php?t=3990

 

[mrwaffles]

That's all very interesting. Why then would the GTX manual state that it needs 36Amps on 12V rail? It seems in that article they just talk about 20Amps on 12V being completely satisfactory. I'm just confused as to why the requirements don't match up with the actual physical requirements. Like jsc was saying why would it suggest 36 amps if the GTX only really requires 14?

 

[srgess]

Yeah well they state that it need 36amp recommended because they don't want customer get mad because they would say its recommended 20amp on 12v rail and they have 10 hard drive and 40 fans that just won't fit, i guess they don't take the risk. I think 14amp is pretty low, Even 20 amp is pretty much the limit. Depend what cpu, ram, hard drive, fans etc.. you running. Higher amp, watt is always better then limit.

 

[delluser1]

Why then would the GTX manual state that it needs 36Amps on 12V rail?

People tend to miss the fact that that is the "system" power recommendation, 14a for the card, maybe 4-8a depending on the cpu, another amp per hard drive and optical drive, a couple three for the mb, maybe 1 or 2a for fans and you don't want to be running the psu to the edge of it's capabilities so a bit of a buffer is figured in.

 

[mrwaffles]

I see. So I shouldn't expect my frame rate to increase any when I get a new PSU? Currently I'm running 30 at 5 on my enermax and the GTX 280 I use (the original poster Chris is a buddy and we're sharing accounts here) I wasn't really satisfied with my 30-45 FPS in Farcry 2 and Crysis (no matter what I set the visual settings too) and I was hoping that it was the Enermax limiting my frame rate, and not my 3.6Ghz Core2Duo E6600.

 

[srgess]

What is your average fps if you do Farcry 2 benchmark tool: Run 1 ,ultra high ,1920x1200, no aa ?

 

[delluser1]

Currently I'm running 30 at 5 on my enermax and the GTX 280

You lost me with that, please explain more clearly.

 

[mrwaffles]

The enermax ratings say it does 30V at 5amps.

 

[mrwaffles]

I can't run 1920x1200 so I did 1280x960, everything very high.

* Total Frames: 2535, Total Time: 51.00s
* Average Framerate: 49.70
* Max. Framerate: 73.37 (Frame:392, 6.65s)
* Min. Framerate: 35.65 (Frame:1734, 34.58s)

That doesn't seem like the kind of preformance you would expect from a GTX 280.

My setup:

core2duo E6600 @ 3.6
Nvidia 680i Motherboard
Enermax 750 Watt PSU
GTX 280 with latest drivers
Vista 64 Service pack 1
4 Gigs G.Skill DDR2 1066 PC8400

 

[Dekasav]

PSUs don't limit framerate, unless your card can't get enough power and is downclocking itself, but it'd be much harsher than what you're experiencing. And I've never seen a PSU that put out a 30 volt rail, are you sure it's not a 5 volt rail at 30 amps? That's pretty common.

Graphics cards run on 12 volts, so that's what's really important.

 

[mrwaffles]

I might have got it backwards and you're probably right. Is that frame rate normal? I'm running Crysis Warhead on the "Gamer" settings at 1280x960 w/ no AA at around 30-45 frames. Is that a normal rate for a GTX 280?

 

[gamerk316]

For a 280, that sounds a bit low; my GX2, which for Crysis is about the same as a 280, gets around 35-45 on highest settings (NO AA, 1650x1080). AA kills Crysis for any setup right now, and you shouldn't try it above 2x at most.

 

[mrwaffles]

So what exactly is killing my frames?

 

[srgess]

I did the same benchmark on my GTX 260 Core 216. I got

# Average Framerate: 54,63
# Max. Framerate: 85,51
# Min. Framerate: 37,96

Just to compare at 1920x1200 at ultra high benchmark i got 46 fps average difference is not large. But first off, if you playing at 1280x960 you didn't took the good card sure it suppose to do better but if you want to do a real test do a 3d vantage mark or 3dmark 06 test. Also your psu is fine. I am running on a 520w psu with 54amp on 12v rail and im sure i could use a gtx280 without any problem. Try 3dmark 06 and come back us with the result.

 

[mrwaffles]

Hi guys sorry it took me awhile to get back to you, I've been busy. I just did a Vantage benchmark and this is my result:

13089 3DMarks

Is that good for this system:
core2duo E6600 @ 3.6
Nvidia 680i Motherboard
Enermax 750 Watt PSU
GTX 280 with latest drivers
Vista 64 Service pack 1
4 Gigs G.Skill DDR2 1066 PC8400

I just got a new PSU and if I get a chance I'll put my new one in tonight and re run the benchmark. This just doesn't seem to be running fast enough for a GTX 280. Something smells amiss.

 

[delluser1]

I am running on a 520w psu with 54amp on 12v rail

That's impossible
54a X 12v = 648w
Check your psu label and see how many watts are available to the 12v rail/rails.
If it's a Corsair520, it's actually a single rail psu with a 40 amp output

 

[mrwaffles]

I just swapped out for a PC Power & Cooling silencer 750 Quad PSU. It has a single rail apparently. 3D Mark Vantage keeps crashing now so I'm trying to figure out what's wrong.

 

[mrwaffles]

So now everything keeps crashing when I try to run it. I used EVGA Precision to check GPU temperature (I haven't overclocked the GPU) and it hits about 77 degrees C when the games/3D Mark crash. How could a new PSU cause my GPU to over heat?