Simple PS > Graf(X) reqs ?

sincraft

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Apr 18, 2006
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I'm looking to pickup a G92 core 512mb GTS here soon and noticed that the power reqs on some sites require 28A? My PS specs are a bit confusing. Can someone clarify what is meant here again for the 28amps? Is that total or on one line?
Here are my PS specs.

Antec SmartPower2.0 450 watt
Maximum Power 450 Watts
Switches ATX Logic on-off
additional power rocker switch
115/230 Volt selector switch
Special Connectors ATX12V
3-pin Fan Sensor
SATA
Transient Response +5V, +12V and 3.3V outputs return to within 5% in less than 1ms for 20% load change.
P. G. Signal 100-500ms
Over Voltage Protection
recycle AC to reset +5V trip point < +6.5V
+3.3V trip point < +4.1V
+12V trip point < +14.4V
Leakage Current < 3.5mA @ 115VAC

DIMENSIONS
Unit Size 5.9"(W) x 3.4"(H) x 6.1"(D)
14.9cm (W)x 8.5cm (H) x 15.8cm (D)
Net Weight 5lbs.; 2.3kg
INPUT
Input Voltage 115 VAC / 230VAC
Input Frequency Range 60Hz/50Hz
Input Surge Current < 60A @ 115VAC
Input Current 12.0A for 115VAC
6 .0A for 230VAC
Hold-up Time > 17ms at Full Load
Efficiency > 70%
EMI/RFI FCC Class B
OUTPUT
+3.3V +5V +12V1 +12V2 +5V SB -12V
Max. Load 32.0A* 30A* 15A* 17A 2.0A 0.3A
Min. Load 0.5A 0.5A 0.4A 0.4A 0A 0A

Load Reg. ±5% ±5% ±5% 5% ±5% ±5%
Ripple V(p-p) 50mV 50mV 120mV 120mV 50mV 120mV
* +5V, +12V1, 12V2 and +3.3V maximum output: 410 Watts max
* +5V and +3.3V combined output: 150Watts
ENVIRONMENTAL
Operating Temp. 10 to 50ºC
Operating Alt. Sea Level 10,000 ft.
Non-Operating Vibration Operating: 10-300 Hz, 0.5G, 3 axes, 1 hr. ea. axis
Non-operating: 10-300 Hz, 2.0G, 3 axes, 1 hr. ea. axis
MTBF 80,000 hrs. @ 25ºC
Approvals UL, TUV, CB, FCC CLASS B, CUL
 
Well you need to know that the 15A+17A does not equal 32Amp

You know that 410W can be pulled from the 3.3, 5 and 12V rails, therefore given that 5V can pull 30A = 150W, the 3.3 can pull 32A = 105W so the remainder can be used on the 12V rail. 410-150-105= 155W remaining, 155/12 = 13A.

However is also says that the max for 3.3+5V = 150A therefore 410-150= 260W which equates to 21.6A (260/12)

It looks to me as if the PSU could cope only if the 3.3V and 5V rails are consuming significantly below their maximum. To reach your desired 28A you'd have to be only using 50% of the total amount available to the 5V and 3.3V rails.

My gut feel is that it's a bit too close to call, and you could kill your PSU and possibly other components.

Simple way around this might be one of those PSU boosters that sit in a 5-1/4 bay. Something like this http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=434414 as your PSU is a good one, and you'd have to spend a lot more to get an equivalent quality of PSU. I'd hate for you to get a lower quality one and then hit other trouble.
 

thepinkpanther

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u see that output graph on ur psu? It says u need 28a on the 12v Rail. Ur psu has two 12v Rails; 12v1, and 12v2. ur 12v1 has 15a and ur 12v2 has 17a. Ur only going 2 use 1 rail for 1 8800gts, ur psu says:

* +5V, +12V1, 12V2 and +3.3V maximum output: 410 Watts max

so in ur case since ur only using 1 rail u would divide 410 by 12 so ur psu is around 34a on the 12v. Any1 correct me if im wrong.
 


I'd say you were wrong, 410/12 assumes that you use 0A on 5V and 3.3V which I think are the voltages that feed the CPU and memory etc. and as they have 30A and 32A available to them I'd assume that they use something.
 

sincraft

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wow that ps booster looks nice. Yea I'd hate to get another PS if I dont have to IF that booster (if in america) is much cheaper than a new ps. I have the tomshardware list of recommended ps, wherever it was I got it from...
But looking at my older system with a sckt 939 and 4200+ chip ..7600gt card, 2 drives in raid, decent memory - I wonder if it's worth spending the money on a g92 gts card AND a ps unless I can transfer both of those (the card and the PS) to a new system in another 1 or 1 and a few months from now, which I might be able to if I play my cards right.

Last famous words coming up: ....And if I were to get a 650w ps, I'm sure I won't need more than that in the future! right! :)

God I was amazed when they started selling 350w supplies.

Yea btw I think 13th monkey is correct. I have to take into account other things that are pulling power from the PS on the other rails.
Keep in mind that this PS is about 1.5 years old, constantly on and at least once a day has a decent amount of juice pulled form it to game for an hour or two. That PS has degraded about 10% I can imagine from it's original specs. SO yea, I am probably cutting it close and will battle with the dreaded phantom system instability if I don't do something about my ps huh?

Unless someone has some hard math to enlighten the topic ???

I tried some of those online calculators which are nice and all, but they do not take the individual ps's into account which seems kinda senseless without that information.
It's equal to saying a truck can pull your boat. What size is the truck and how big is the boat. Are you going up hills or just traveling on highways. There's much more to the equation that those sites don't take into account. Or maybe I hit the wrong sites and there are some that allow you to enter your ps specs?

S