Power supply requirement for 2 Nvidia GTX in SLI?

OK, my system:

AMD 6400 AM2 Processor
Asus M2N SLi Deluxe Mobo
4 Gig RAM
1 250GB Sata, 2*400GB Sata Drives
2x Nvidia 768M 8800GTX
XFi extreme gamer soundcard

My question is what size PSU will I need to run this lot when gaming?

Will a Hiper 730W do the trick??

--
huLLy
Tel 07976 123278

'huLLy' wrote:
My question is what size PSU will I need to run this lot when gaming? OK,
my system:

AMD 6400 AM2 Processor
Asus M2N SLi Deluxe Mobo
4 Gig RAM
1 250GB Sata, 2*400GB Sata Drives
2x Nvidia 768M 8800GTX
XFi extreme gamer soundcard

My question is what size PSU will I need to run this lot when gaming?

Will a Hiper 730W do the trick??
_____

Never heard of a 'Hipper' brand power supply, but if it is decent and really
is rated at 730 Watts continuous operation, yes, 730 Watts is plenty for
total power; just make sure that the + 12 VDC rails can provide the
necessary current:

CPU: ~ 12 Amperes for the 12 DC-DC down converter-regulator

PLUS

8800 GTX: ~ 12 Amperes Peak Load each (see
http://www.xbitlabs.com/articles/vid...p_6.html#sect0 ) PLUSeach drive, a max of ~ 2 Amperes when spinning up from stopped to fullspeed, ~ 1/2 Ampere otherwise (3 drives plus, I assume an optical drive?)PLUSa few Amperes for everything else.That's a total of 45 Amperes from the +12 VDC rails (there may be from oneto three +12 VDC rails), 540 Watts max. Add 100 Watts or so are from the +5 VDC and +3.3 VDC rails (memory, motherboard, drives,audio card.) Addanother 5 Watts or so for + 5 VDC Standby, perhaps nothing at all for the -12 VDC (the audio card MIGHT use -12 VDC, nothing else will), - 5 VDC is nolonger even provided. The grand total will be under 650Watts (the currentallowances for the CPU, 8800 GTX's, and drives are generous.)The present standard for ATX power supplies is ATX 12V ver. 2.31 (see http://www.formfactors.org/developer...V_1_3dg.pdfand http://www.formfactors.org/developer..._Rev_1_2 .pdf )include 'current sharing' among the +12 VDC rails, the +5 VDC rails, and the+3.3 VDC rails so that much of the unneeded current capacity of the lowervoltage rails can be used by the +12 VDC rails (up to the rated maximum.)HOWEVER, you might feel more comfortable with a good power supply with a 850Watt rating; after all, you are spending more $1000 for your displayadapters, so the incremental cost of going from a 730 Watt to a 850 Wattsupply is a small percentage of the system cost. And, as always, a welldesigned and constructed power supply with a lower rated capacity may outperform a poor quality power supply with a higher rating. (Seehttp://www.xbitlabs.com/ for power supply ratings and reviews.)Phil Weldon"huLLy" wrote in messagenews:ToidnTsWI9R5MUranZ2dnUVZ8qqdnZ2d@gigan ews.com... OK, my system: AMD 6400 AM2 Processor Asus M2N SLi Deluxe Mobo 4 Gig RAM 1 250GB Sata, 2*400GB Sata Drives 2x Nvidia 768M 8800GTX XFi extreme gamer soundcard My question is what size PSU will I need to run this lot when gaming? Will a Hiper 730W do the trick?? -- huLLy Tel 07976 123278

huLLy wrote:
OK, my system:

AMD 6400 AM2 Processor
Asus M2N SLi Deluxe Mobo
4 Gig RAM
1 250GB Sata, 2*400GB Sata Drives
2x Nvidia 768M 8800GTX
XFi extreme gamer soundcard

My question is what size PSU will I need to run this lot when gaming?

Will a Hiper 730W do the trick??


I get a total of about 12V @ 37.1A, but it will be spread
across the rails, according to how the output is wired.
Some supplies use a single 12V output, which means not
having to figure out the distribution.

For total power I get (approximately) -

(12*37.1) + 50 + 3*5 + 1*7.5 + 10 = 528W

There is a manual for a 730W supply here.

http://www.hipergroup.com/English/do..._datasheet.pdf

Tracking where the +12V current flows, gives this. The
four PCI Express connectors, are spread one per rail.
That really isn't the best way of distributing the loading,
as the processor load on 12V2 is pretty significant, and
so 12V2 really shouldn't be used for more than the processor.

Video card = 12V_slot + 12V_EXT1 + 12V_EXT2
= 3.67A + 3.58A + 3.42A

Power supply rails, and resulting load distribution (0.5A for
fans, 3.3A for 3 hard drives and 1 optical drive)

PCI-Express 12V1 3.58 = 3.58A
ATX Main + PCI-Express 12V3 3.67 + 3.67 + 0.5 + 3.58 = 11.42A
ATX12V 2x2 + PCI-Express 12V2 12 + 3.42 = 15.42A
Drives + PCI-Express 12V4 3.3A + 3.42 = 6.72A

The Hiper supply could do the job. Or the following
Silencer 750W would also be suitable. This one uses
a single 12V rail, such that the user doesn't have to
worry about how the rail limits, like the ones above,
are policed by the supply.

Silencer 750
http://www.newegg.com/Product/Produc...82E16817341011

Paul

Paul wrote:
huLLy wrote:
OK, my system:

AMD 6400 AM2 Processor
Asus M2N SLi Deluxe Mobo
4 Gig RAM
1 250GB Sata, 2*400GB Sata Drives
2x Nvidia 768M 8800GTX
XFi extreme gamer soundcard

My question is what size PSU will I need to run this lot when gaming?

Will a Hiper 730W do the trick??


I get a total of about 12V @ 37.1A, but it will be spread
across the rails, according to how the output is wired.
Some supplies use a single 12V output, which means not
having to figure out the distribution.

For total power I get (approximately) -

(12*37.1) + 50 + 3*5 + 1*7.5 + 10 = 528W

There is a manual for a 730W supply here.

http://www.hipergroup.com/English/do..._datasheet.pdf


Tracking where the +12V current flows, gives this. The
four PCI Express connectors, are spread one per rail.
That really isn't the best way of distributing the loading,
as the processor load on 12V2 is pretty significant, and
so 12V2 really shouldn't be used for more than the processor.

Video card = 12V_slot + 12V_EXT1 + 12V_EXT2
= 3.67A + 3.58A + 3.42A

Power supply rails, and resulting load distribution (0.5A for
fans, 3.3A for 3 hard drives and 1 optical drive)

PCI-Express 12V1 3.58 = 3.58A
ATX Main + PCI-Express 12V3 3.67 + 3.67 + 0.5 + 3.58 = 11.42A
ATX12V 2x2 + PCI-Express 12V2 12 + 3.42 = 15.42A
Drives + PCI-Express 12V4 3.3A + 3.42 = 6.72A

The Hiper supply could do the job. Or the following
Silencer 750W would also be suitable. This one uses
a single 12V rail, such that the user doesn't have to
worry about how the rail limits, like the ones above,
are policed by the supply.

Silencer 750
http://www.newegg.com/Product/Produc...82E16817341011

Paul

That was nice of you to do all that work for the OP, I hope he
appreciates it.

Mr.E Solved! wrote:
Paul wrote:
huLLy wrote:
OK, my system:

AMD 6400 AM2 Processor
Asus M2N SLi Deluxe Mobo
4 Gig RAM
1 250GB Sata, 2*400GB Sata Drives
2x Nvidia 768M 8800GTX
XFi extreme gamer soundcard

My question is what size PSU will I need to run this lot when gaming?

Will a Hiper 730W do the trick??


I get a total of about 12V @ 37.1A, but it will be spread
across the rails, according to how the output is wired.
Some supplies use a single 12V output, which means not
having to figure out the distribution.

For total power I get (approximately) -

(12*37.1) + 50 + 3*5 + 1*7.5 + 10 = 528W

There is a manual for a 730W supply here.

http://www.hipergroup.com/English/do..._datasheet.pdf


Tracking where the +12V current flows, gives this. The
four PCI Express connectors, are spread one per rail.
That really isn't the best way of distributing the loading,
as the processor load on 12V2 is pretty significant, and
so 12V2 really shouldn't be used for more than the processor.

Video card = 12V_slot + 12V_EXT1 + 12V_EXT2
= 3.67A + 3.58A + 3.42A

Power supply rails, and resulting load distribution (0.5A for
fans, 3.3A for 3 hard drives and 1 optical drive)

PCI-Express 12V1 3.58 = 3.58A
ATX Main + PCI-Express 12V3 3.67 + 3.67 + 0.5 + 3.58 = 11.42A
ATX12V 2x2 + PCI-Express 12V2 12 + 3.42 = 15.42A
Drives + PCI-Express 12V4 3.3A + 3.42 = 6.72A

The Hiper supply could do the job. Or the following
Silencer 750W would also be suitable. This one uses
a single 12V rail, such that the user doesn't have to
worry about how the rail limits, like the ones above,
are policed by the supply.

Silencer 750
http://www.newegg.com/Product/Produc...82E16817341011

Paul

That was nice of you to do all that work for the OP, I hope he
appreciates it.

The part that bothers me about these multi-rail supplies, is whether
they'd actually get upset, if the rating printed on the label is
exceeded. That supply is a quad 16 amp, and the 12V2 is getting
pretty close to the limit. Some of the good sites that review
power supplies, find they can double the load on a single rail,
without the supply shutting off. I feel guilty doing the analysis,
like the one I attempted above, when I don't know for a fact that
the supply "tips over" at 16A. But I have to follow what I see on
the label, and pretend that what is printed on the label, is
gospel.

Paul

As you know, some power supplies made by Seasonic and PCP&C are really
single-rail, but were advertised as multi-rail at one time because it was
fashionable. Now single-rail supplies are trendy, you see all kinds of
monster PSUs re-labeled with 50A or even 70A ratings on the 12V.

--
"War is the continuation of politics by other means.
It can therefore be said that politics is war without
bloodshed while war is politics with bloodshed."

"Paul" wrote in message ...
The part that bothers me about these multi-rail supplies, is whether
they'd actually get upset, if the rating printed on the label is
exceeded. That supply is a quad 16 amp, and the 12V2 is getting
pretty close to the limit. Some of the good sites that review
power supplies, find they can double the load on a single rail,
without the supply shutting off. I feel guilty doing the analysis,
like the one I attempted above, when I don't know for a fact that
the supply "tips over" at 16A. But I have to follow what I see on
the label, and pretend that what is printed on the label, is
gospel.

Paul

First of One wrote:
As you know, some power supplies made by Seasonic and PCP&C are really
single-rail, but were advertised as multi-rail at one time because it was
fashionable. Now single-rail supplies are trendy, you see all kinds of
monster PSUs re-labeled with 50A or even 70A ratings on the 12V.


I just wish the industry had some standards for this. It shouldn't boil
down to some review site opening the thing with a screwdriver, to figure
out how it works, and how it can be used.

Paul

Mr.E Solved! wrote:

That was nice of you to do all that work for the OP, I hope he
appreciates it.

When Paul did the same work for me ... it was well appreciated - it's
helpful folks like Paul that make NG's tolerable IMO.

Boff.

"huLLy" wrote in message
...
OK, my system:

AMD 6400 AM2 Processor
Asus M2N SLi Deluxe Mobo
4 Gig RAM
1 250GB Sata, 2*400GB Sata Drives
2x Nvidia 768M 8800GTX
XFi extreme gamer soundcard

My question is what size PSU will I need to run this lot when gaming?

Will a Hiper 730W do the trick??

--
huLLy
Tel 07976 123278
I use a PC Power and Cooling Silencer 750 that comes with the necessary "4"
power connectors for two 8800 GTXs in SLI. PCP&C have been around virtually
forever and make very good quality PSUs.

Ed