So after a LOT of trials and tribulations, I finally have 2 970's running in my 5.1 cMP. My first foray was with a flashed 680, which had all kinds of issues. It'd lock up the entire box mid render, would corrupt the video display, and I suspect the card itself was bad. However, it greatly sped up the blender Renders of the stuff I'm modeling in Rhino. I further determined that using the card for running the monitors DID put a render time hit, so pulled out a spare GT120 that the cMP's shipped with, stuffed that in slot 4 and plugged my 2 24" 1920x1200 Dells into that. That was worth about an 18% increase in render speed. That doesn't seem like much until you have render times running well over 3 days for a 10 second anim. I don't game at all, so could care less about the card's performance in the display arena. It'll play a 1920x1080 QT @ 24 FPS without flinching, so that's fine for my stuff. So after returning the faulty flashed GTX680, I picked up a EVGA GTX970SC. That worked great once I got the security patch related driver issues sorted out. After reading Machine's post with the guy in the UK using a pair of cards off the 2 6 pins with splitter cables, and doing a several day render while running hardware monitor and not seeing any wattage pulls of over 36 watts on the boost line, I figured I could give a second card a go. So I ordered the splitters off the guy on EBay (got here in 2 days, whee), and hopped over to Fry's to pick up a second 970. Dunno what it is with EVGA but do they have to have 9 different flavors of the week for each of these cards? Got home before I realized the card was not even close to the same as the 970SC. This one was the "SSC" and the card was longer (bout an inch), and took a 6 pin AND and 8 pin, where as the "SC" only took 2 6 pins. That didn't bode well, so I pulled the existing 970 out, broke out EVGA's dual six to single 8 pin cable adapter and plugged it in. It booted (probably because my video is of the GT120) although in system info it showed up as a Nvidia Video Card with 256 MB of VRAM. That didn't look promising. Cuda-Z caused it to lock up the box completely the second it launched. Rebooted again and fired up blender and it didn't recocognize the 970 SSC as even having a GPU. Rather than jack around with it I took that card back and looked for another 970 SC, but they didn't have any, although they did have a 970 FTW, which according to the box also had 2 6 pins as it's power input. Ok fine, we'll try that. Got it out of the box and it's the same length as the SC, although it's fin layout for the cooling is slightly different and some other components are in different places. It is a different board. How different? Who knows. Put the 970 FTW in by itself, and it looked correct according to the system report, CUDA-Z showed it correctly, and it showed up in blender. So I dropped in the second 970 (the previously pulled SC) hooked up the splitter cables and powered up the box. Booted fine (10 second boots on a Samsung 1TB EVO 850), CUDA-Z showed both cards available and reporting (practically no difference in the various values on the performance tab between the 970 SC and the 970 FTW. For comparison here's the results of the 2nd Mike Pan Render benchmark (the one with 2 BMW's) in Blender: This on a 2x 2.26 Quad Core Xeon 5.1 box running OS X 10.10.2 CPU Only on GTX 285: 04:37.58 GPU On Flashed GTX 680 4GB: 01:50.37 (320 x 270 Tile) GPU On Single EVGA GTX 970 SC 4GB: 01:22:50 (320 x 270) GPU On EVGA GTX 970 SC 4GB + EVGA GTX 970 FTW 4GB: 0:44:44 (320 x 270) Render times on my own benchmark of what's my normal type of thing I'm rendering: CPU GTX 285 Mac Version: 21:25.18 GPU Single EVGA GTX680 4GB Mac Flashed Rom: 12:48.15 GPU Single EVGA GTX 970 SC 4GB: 07:36:31 (320 x 270) GPUS EVGA GTX 970 SC 4 GB + EVGA GTX 970 FTW 4 GB: 03:51.91 I'd say it's well worth the performance increase for the pair of the cards. With both cards going full tilt on renders HW Monitor is reporting: 327W total (PS 1 Line 1) 47.2W PCIE Slot 1 12V Line 46.7W PCIE Slot 2 12V Line 32.8W PCIE Slot 1 12V Boost Line 29.9W PCIE Slot 2 12V Boost Line 13.2W PCIE Slot 4 12V Line (The GT120 video card driving the monitors). I'd say this is well in the safe zone. For a single box, no re wiring, no external or internal 2nd PS for about $650 out of pocket to go from over 21 minutes a frame just under 4 and cut my render times from 85 hours to 15? Oh hells yeah. Close to a 6X improvement. I'll take that any day of the week. Can't even buy a single 980 for that, let alone a TitanX. Cheers.