For those interested in mining with GTX 750's here is an eBay link to what I am currently purchasing.
https://www.ebay.com/itm/ZOTAC-NVIDIA-GeForce-GTX-750-1-GB-GTX750-1GD5-Video-Card-128bit-DVI-HDMI-VGA/142732559955These GTX 750's are Zotac branded, have the full double wide bracket (easier to attach to mining frames) and can be easily overclocked. I am getting around 245 H/s at 38.5 watts on these.
Another good thing is that these need no additional power cables as they get all their power from the PCIe slot. With the power draw being so low you can use risers that are powered with SATA to 6-pin cables.
Would you mind posting a pic showing how you've set these up? I'm assuming you've mounted a mining case on top of the chassis. I've got one PCIe expansion card that I can use. The other system doesn't have one, but if I can set the first one up it shouldn't be a big deal to find another board.
And do you think Linux Mint would work for an O/S?
The 750's are definitely cheap enough, but I'm also wondering about using 770's and 950's, of which I have several of sitting here collecting dust. Power usage on the 770's may be way out of line though.