Asus GTX 780

hal9000Mark2

macrumors newbie
Original poster
Aug 30, 2009
6
0
Hi guys,

I'm thinking about getting the Asus GTX 780. I want to make sure that it'll work with Mac Pro 3,1. I'm not bothered by link speed or boot screen.

I noticed that there are two spare SATA ports (they are called "odd sata") on my motherboard. I'm thinking of using the 2x 6-pin ports for the 8-pin on the GTX and the two SATA ports for the 6-pin on the GTX using this adaptor http://www.amazon.co.uk/gp/product/B007Y91B80/ref=oh_details_o02_s00_i00?ie=UTF8&psc=1.

Do you think this would be work? How much power does a SATA port give?

PCIE = 75W
2x6 pin = 150W
2xSATA = ??

Thanks for any help!
Hal

----------

So I just did a bit of research. SATA ports carry 15 pins, of which 9 are power. 3x3.3V, 3x5V and 3x12V with 1.5amps each pin.

A bit of maths ( http://www.rapidtables.com/calc/electric/Amp_to_Watt_Calculator.htm ) we get:

3pins x 12V = 54 W

2xPorts = 108W

Does that seem right?

Thanks!
 

slughead

macrumors 68040
Apr 28, 2004
3,105
234
The ports on your mobo are SATA data ports. Not SATA power ports.
I think he's talking about the "SATA" power ports



As far as your math, OP, you're technically correct: The PCIe, the on-board 6 pin, and the SATA ports can conduct enough amperes to power the card.

However, you have 6 x 12v leads entering the card, how do you make sure one doesn't draw too much power from the sata power, melting the connector? If it melts one connector, it'll melt the other one for sure shortly after, then you're left with the motherboard tracers and it's unclear how long they'll hold out.

Maybe you could build a circuit to limit / cut off the extra amperes, or maybe you could solder all the 12v leads together and hope for the best.

I don't know if the setup you're talking about would work or not, perhaps the physics majors can chime in?

Also, does anyone know how many 12v rails are in the MP PSU?