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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 |
#2
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Power supply requirement for 2 Nvidia GTX in SLI?
'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 |
#3
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Power supply requirement for 2 Nvidia GTX in SLI?
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 |
#4
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Power supply requirement for 2 Nvidia GTX in SLI?
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. |
#5
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Power supply requirement for 2 Nvidia GTX in SLI?
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 |
#6
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Power supply requirement for 2 Nvidia GTX in SLI?
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 |
#7
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Power supply requirement for 2 Nvidia GTX in SLI?
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 |
#8
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Power supply requirement for 2 Nvidia GTX in SLI?
'Paul' wrote:
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 _____ There IS a standard; see http://www.formfactors.org/developer...X12V_1_3dg.pdf and http://www.formfactors.org/developer..._Rev_1_2 .pdf ) .. The idea behind the separate current limited + 12 VDC rails is to avoid a fault condition that can draw 500 or more Watts before safety circuits kick in. Phil Weldon "Paul" wrote in message ... 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 |
#9
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Power supply requirement for 2 Nvidia GTX in SLI?
Phil Weldon wrote:
'Paul' wrote: 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 _____ There IS a standard; see http://www.formfactors.org/developer...X12V_1_3dg.pdf and http://www.formfactors.org/developer..._Rev_1_2 .pdf ) . The idea behind the separate current limited + 12 VDC rails is to avoid a fault condition that can draw 500 or more Watts before safety circuits kick in. Phil Weldon "Paul" wrote in message ... 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 I've heard of the 240VA limit from IEC60950, but it appears to be optional to support it. http://www.pcpower.com/technology/myths/ "PC Power and Cooling is once again leading the industry. All of our power supplies now feature a large, single 12-volt rail. The design is favored by major processor and graphics companies, complies with EPS12V specs (the 240VA limit is not a requirement) and is approved by all major safety agencies such as UL and TUV.3" I'm not going to argue the merits of that statement, because I don't have a copy of the appropriate spec that calls up the 240VA limit. I understand it is traceable to something like 60950, but don't have a copy. I was referring more to the architecture of the supplies. While formfactors has a design document for dual rail supplies, I'm not aware of any standard for tri or quad rail supplies. (Maybe design guidance comes from some server spec ?) And the assignment of connectors, seems to be largely left to chance. On the plus side, I am finding more documentation than I used to. A few years ago, it used to be really frustrating to find out what the wiring plan was. (Took a review article, to get the story. The manufacturer couldn't be bothered to list it.) Paul |
#10
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Power supply requirement for 2 Nvidia GTX in SLI?
'Paul' wrote:
I'm not going to argue the merits of that statement, because I don't have a copy of the appropriate spec that calls up the 240VA limit. I understand it is traceable to something like 60950, but don't have a copy. _____ See "3.4.4. Over-current Protection Overload currents applied to each tested output rail will cause the output to trip before reaching or exceeding 240 VA. For testing purposes, the overload currents should be ramped at a minimum rate of 10 A/s starting from full load." on page 22 at http://www.formfactors.org/developer...X12V_1_3dg.pdf . Notice the phrase 'will cause the output to trip'. and 8.1 North America - REQUIRED The power supply must be certified by an NRTL (Nationally Recognized Testing Laboratory) for use in the USA and Canada under the following conditions: .. The power supply UL report "Conditions of Acceptability" shall meet in the intended application of the power supply in the end product. .. The supply must be recognized for use in Information Technology Equipment including Electrical Business Equipment per UL 60950-1 First Edition. The certification must include external enclosure testing for the AC receptacle side of the power supply (see Appendices A, B, C, and D). .. The supply must have a full complement of tests conducted as part of the certification, such as input current, leakage current, hi-pot, temperature, energy discharge test, transformer output characterization test (open-circuit voltage, short-circuit performance), and abnormal testing (to include stalled-fan tests and voltage-select-switch mismatch). on page 45 at http://www.formfactors.org/developer..._Rev_1_2 .pdf . And see "If the selected power supply has any single output rated at more than 240VA contact with circuits connected to the output must be prevented in user access areas, protection may be achieved by insulation, guarding or interlocks (refer to IEC 60950-1 First Edition, 2001 Clauses 0.2.2 and 2.1)" at http://www.intel.com/cd/channel/rese.../eng/35831.htm . And, finally, see 'UL 60950-1 Information Technology', page 80 at http://www.psui.com/1upower/pdf/901_ref.pdf . Phil Weldon "Paul" wrote in message ... Phil Weldon wrote: 'Paul' wrote: 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 _____ There IS a standard; see http://www.formfactors.org/developer...X12V_1_3dg.pdf and http://www.formfactors.org/developer..._Rev_1_2 .pdf ) . The idea behind the separate current limited + 12 VDC rails is to avoid a fault condition that can draw 500 or more Watts before safety circuits kick in. Phil Weldon "Paul" wrote in message ... 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 I've heard of the 240VA limit from IEC60950, but it appears to be optional to support it. http://www.pcpower.com/technology/myths/ "PC Power and Cooling is once again leading the industry. All of our power supplies now feature a large, single 12-volt rail. The design is favored by major processor and graphics companies, complies with EPS12V specs (the 240VA limit is not a requirement) and is approved by all major safety agencies such as UL and TUV.3" I'm not going to argue the merits of that statement, because I don't have a copy of the appropriate spec that calls up the 240VA limit. I understand it is traceable to something like 60950, but don't have a copy. I was referring more to the architecture of the supplies. While formfactors has a design document for dual rail supplies, I'm not aware of any standard for tri or quad rail supplies. (Maybe design guidance comes from some server spec ?) And the assignment of connectors, seems to be largely left to chance. On the plus side, I am finding more documentation than I used to. A few years ago, it used to be really frustrating to find out what the wiring plan was. (Took a review article, to get the story. The manufacturer couldn't be bothered to list it.) Paul |
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