i have a 2010 Mac Pro with an ATI 5870 that i mainly use with Windows 7 Boot Camp. i needed to install a second graphics card, but could not find a way to power it since the 5870 was using the two existing 6-pin PCIe power cables. at first, i purchased a Quadro 4000 for Mac and powered it by splitting one of the two PCIe cables with a PCIe Y-Splitter. everything worked great, although it made me nervous to split the power from one 6-pin PCIe cable.
than i returned the Quadro 4000 for Mac for the more powerful Quadro 5000 which also requires one extra 6-pin PCIe cable that the Mac Pro does not have. to remedy the situation, i purchased an external Seasonic X-Series 660W modular power supply. i ran two PCIe cables from the external power supply in through the top-most PCI slot (an empty slot) into the 5870, and used one of the two existing internal PCIe cables to power the Quadro 5000. after jumping the external power supply's motherboard connector with a paperclip and electrical tape, everything seems to be working great in Windows 7 Boot Camp. i just have to remember to turn the external power supply on and off. here are some pics
than i returned the Quadro 4000 for Mac for the more powerful Quadro 5000 which also requires one extra 6-pin PCIe cable that the Mac Pro does not have. to remedy the situation, i purchased an external Seasonic X-Series 660W modular power supply. i ran two PCIe cables from the external power supply in through the top-most PCI slot (an empty slot) into the 5870, and used one of the two existing internal PCIe cables to power the Quadro 5000. after jumping the external power supply's motherboard connector with a paperclip and electrical tape, everything seems to be working great in Windows 7 Boot Camp. i just have to remember to turn the external power supply on and off. here are some pics
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