Mac pro 2009 Max power draw on SATA optical bay cables
I just picked up a early 2009 4,1 Mac Pro to replace my current 2,1 Mac Pro.
In the 2,1 I'm running a custom flashed radeon 7970 with 6+8 pin power connectors. Currently in the 2,1, the 8 pin on the card is being powered by the two molex connectors for the optical drives via a converter, and the 6 pin on the card is powered by one of the connectors on the motherboard. (the second connector on the motherboard is broken om my 2,1)
Now my new machine (the 4,1) has SATA power in the optical bay, and the power spec for SATA is quite a bit lower than for the molex connectors. Would I be OK running the 6-pin on the card from the SATA power in the optical bay, and the 8-pin from both the mini 6 pins on the motherboard combined?
If I calculated properly, I should be able to draw 54W from each SATA connector at 12v (1,5A per cable, 3 cables with 12V so total of 4,5a at 12V = about 54W). 6-pin PCIe power has a max draw of 75W, so 108W from both SATA power cables should be easily enough, but since both SATA power plugs in the optical bay are powered by a single cable that splits in to two connectors, I would like to confirm this before I fry my board.
The SATA power seems to be coming from one connector on the motherboard marked "ODD PWR", can anyone confirm that? And dose anyone know the pinout for this connector? Plugging in a converter cable up in the optical bay and running it back down to the GPU seems a bit of a unnecessary hassle if I could just adapt the 6-pin directly from the 4 pin on the motherboard of the Mac Pro.
(I don't mind having to solder my own converter cables, I'm probably going to do that anyway to get them to the exact right lengths)
After measuring the connector on the board and the SATA power connector on the other end and comparing the results with the pinout of the SATA power connector I've managed to discover the pinout of the connector, and verified it by mesuring the connector on the motherboard with a multimeter with the machine turrned on.
When looking at the machine from the side pannel side:
- Top left = +12V DC
- Top right = +5V DC
- Bottom left & right = GND (same for both 5V and 12V)
Surprisingly no 3,3V present on the connector.
Is this a good question?