The halfling (half-length) PCIe NVidia GeForce 970 card I ordered required 1 PCIe 3 slot, but also needs physical clearance for the connectors to poke out through 2 slots in the back of the Chassis. So form-factor planning can be a bitch. The Free Geek chassis I’m using has all the PCI slots free (including a PCIe 2), so plenty of holes int eh metal chassis, but the PCIe 2.0 slot is at the wrong end of the series, and the Nvidia card needs the blocked side for its connectors. back to New Egg she goes.

HPC Node

Motherboard: PCIe 3.0 slots, Intel CPU socket, i5 or i7 CPU at 2+ GHZ Cheap RAM: 16 GB GPU supports cuDNN: GTX 780 TI, GTX 680, Titan, GTX 980, GTX 960, Maxwell GPU (GTX Titan X, GTX 960, GTX 970, GTX 980)

Kepler and Higher Compute Version (Cuda 3.0+) GeForce GTX 770, GeForce GTX 760, GeForce GT 740, GeForce GTX 690, GeForce GTX 680, GeForce GTX 670, GeForce GTX 660 Ti, GeForce GTX 660, GeForce GTX 650 Ti BOOST, GeForce GTX 650 Ti, GeForce GTX 650, GeForce GTX 880M, GeForce GTX 780M, GeForce GTX 770M, GeForce GTX 765M, GeForce GTX 760M, GeForce GTX 680MX, GeForce GTX 680M, GeForce GTX 675MX, GeForce GTX 670MX, GeForce GTX 660M, GeForce GT 750M, GeForce GT 650M, GeForce GT 745M, GeForce GT 645M, GeForce GT 740M, GeForce GT 730M, GeForce GT 640M, GeForce GT 640M LE, GeForce GT 735M, GeForce GT 730M, Quadro K5000, Quadro K4200, Quadro K4000, Quadro K2000, Quadro K2000D, Quadro K600, Quadro K420, Quadro K500M, Quadro K510M, Quadro K610M, Quadro K1000M, Quadro K2000M, Quadro K1100M, Quadro K2100M, Quadro K3000M, Quadro K3100M, Quadro K4000M, Quadro K5000M, Quadro K4100M, Quadro K5100M, Tesla K10 3.2 GK20A Jetson TK1 (Tegra K1) 3.5 GK110, GK208 GeForce GTX TITAN Z, GeForce GTX TITAN Black, GeForce GTX TITAN, GeForce GTX 780 Ti, GeForce GTX 780, GeForce GT 640 (GDDR5), GeForce GT 630 v2, GeForce GT 730, GeForce GT 720, GeForce GT 710, Quadro K6000, Quadro K5200, Tesla K40, Tesla K20x, Tesla K20, GeForce GT 740M (64-bit, DDR3)