OK, so I'm renaming this thread because I've transitioned away from the idea of running the GTX 690 on the MacPro4,1's internal PSU and the plan is to now use an external PSU (Seasonic Platinum 860W) to power the card. More power than what's needed to run one GTX 690, and really future proofing for a potentially 2nd GTX 690 using the same power supply, but I digress . . . I'm currently seeking a solution that will allow my external PSU to power up/down and sleep/wake with my workstation. The basic idea is if the external PSU is in sync with the internal PSU, the GTX 690 will also be in sync (and thus acting like a normal PCIe powered graphics card). The best solution I've found is the Add2Psu. Here's the link for the Add2Psu adapter: http://www.add2psu.com My "original" plan with the Add2Psu was: SATA 15-pin connection (from 2nd optical drive bay) > SATA 15-pin to Molex 4-pin adapter > Molex extension cable > Add2Psu > 24-pin power supply cable > external PSU The Molex cable would run out through the back of an open PSI slot cover into the Add2Psu and eventually into the external PSU. However, getting the Molex cable out through the optical bay has proved beyond challenging, and I'd prefer not to splice the Molex cable simply to feed the wires through the very small openings out of the optical bay. And feeding the Molex extension cable through the optical drive tray cover is also not an option. The 2nd more viable option I'd like to : PCIe 6-pin connection on motherboard > PCIe 6-pin to Molex 4-pin adapter > Molex extension cable > Add2Psu > 24-pin power supply cable > external PSU The path out from the PCIe 6-pin connection through the PCI slot cover is MUCH easier to navigate than the optical bay. My question is, will the PCIe 6-pin provide the correct voltage necessary to power on/off, sleep/wake the external PSU via the Add2Psu? Will it provide too much wattage than what's actually necessary? Also, if anyone has a more practical idea, it would be very much welcomed!