Okay, there's a terminology problem here.
When we say 6-pin or 8-pin, we mean the 6/8 pin
PCI-E power cables. EVGA G2 750w has four.
Basically, you could use a 8pin PCI-E splitter and connect it to both the RX GPU and direct to the riser's 6 pin socket.
Alternately, it's possible to get (or make) cables that convert the PSU's second CPU EPS12V 8pin connector into a pair of 6/8pin PCI-E and use them to power a pair of risers.
Example:
http://www.ebay.com/itm/CPU-8Pin-to-Graphics-Video-Card-Double-PCI-E-PCIe-Power-Supply-Splitter-Cable-/272720358725Or.... for the risers with the direct molex connection, you could obtain more EVGA G2 compatible molex cables, as for an EVGA G2 all the SATA/PERF sockets on the back of PSU are wired identical/interchangable. (EVGA G2, G1 and GS all use the same pinout for the molex cable)
O.M.G.
That. That is exactly what I was confused about. And it's sitting right under my nose.
So given I want to run 7 cards on one mobo, and I have 8 PCI-E (VGA) cables amongst 2 PSUs.
PSU 1Mobo + CPU
GPU1: VGA1 + Perif-1 to Molex string (1 of 4)
GPU2: VGA2 + Perif-1 to Molex string (2 of 4)
GPU3: VGA3 + VGA4 (to 6-pin riser)
PSU 2GPU4: VGA5 + Perif-2 to Molex string (1 of 4)
GPU5: VGA6 + Perif-2 to Molex string (2 of 4)
GPU6: VGA6 + CPU to 6/8 splitter (OR buy a 8pin to 8pin PCI splitter for both)
GPU7: VGA8 + CPU to 6/8 splitter (OR buy a 8pin to 8pin PCI splitter for both)
Is that right? That makes so much more sense now...!