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steviewhy

macrumors regular
Original poster
Oct 12, 2011
112
2
Does anyone happen to know the power draw of this card. I can't find it documented anywhere including their site. The reason I ask is I don't want to overdraw the pci-e 300 watt total combined limit when I upgrade my video card.

Anyone know?
 

TzunamiOSX

macrumors 65816
Oct 4, 2009
1,012
411
Germany
I see a maximum of 1 Ampere in my 7 days timeline.

P = U x I
P = 12V x 1A
P = 12 Watt

But what are you talking about? 300 Watt total combined? The Mac Pro PSU has 5 rails, but no one can really say, which rail is for what. If you want a GPU who need over 225 Watt it is better to use a Aux PSU.
 

steviewhy

macrumors regular
Original poster
Oct 12, 2011
112
2
I see a maximum of 1 Ampere in my 7 days timeline.

P = U x I
P = 12V x 1A
P = 12 Watt

But what are you talking about? 300 Watt total combined? The Mac Pro PSU has 5 rails, but no one can really say, which rail is for what. If you want a GPU who need over 225 Watt it is better to use a Aux PSU.

Thanks for that. That 12 Watts is pretty low so it shouldn't be a problem. The 300 Watt total I was referring to is the total watts that all of the pci-e slots combined can equal. I was toying with the idea of dropping a pc gtx770 (230 Watt) in there but it's not worth the gamble. Or maybe it is. :D
 

h9826790

macrumors P6
Apr 3, 2014
16,614
8,546
Hong Kong
For your info.

My 7950 also draw about 230W under full load. It only get about 50W from the PCIe slot, the other 180W from the 6 pin cables.

Even though it draw 75W or even 100W from a single PCIe slot, it still far from the 300W limit.
 

TzunamiOSX

macrumors 65816
Oct 4, 2009
1,012
411
Germany
300 Watt is 75 Watt for each of the 4 Slots. 75 x 4 = 300

BUT: You can't get 300 Watt form only one PCIe slot. If you install a GPU you get 75 Watt from the PCI and the rest from the GPU power connectors.
The cMP has 2 x 75 Watt GPU power connectors. If your GPU need more then 225 Watt (1 x 75 Watt PCIe + 2 x 75 Watt GPU connector) you need a AUX PSU or you get the power from other sources like the HD connector.

You think, 5 Watt more is not a problem i will use an Adapter! But there is a problem. The 770 has a 8 Pin connector who can pull up to 150 Watt (2 x 75) and the the power is split approximately evenly to all connectors. 230 Watt / 4 = 57,5 Watt

So you can get:
PCIe ~ 57,5 Watt
GPU con 1 ~ 57,5 Watt
GPU con 2 (with a 8 to 6 adapter) ~ 115 Watt (not good)

But perhaps when you downclock the 770 to 225 Watt (-5 Watt) this can eliminate the 115 Watt problem. But it is better to ask guys like MacVidCards about this.
 
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