Installing GTX 780 Ti in 2010 Mac Pro

So I’ve finally gotten all the components but it seems that I’d not given any thought to power supply cables; my old 2008 Mac Pro had a GTX 680 in it, which used the exact same cables as my previous Radeon HD 5870 (2x 6 pin), but the GTX 780 Ti (and I understand, the ordinary GTX 780 too) has 1x 8 pin and 1x 6 pin. The card itself came with a Y-adapter to convert 2x 6 pin into one 8 pin connector, but whilst I could connect it with this I’d be left short by 1x 6 pin.

I think I’ve got...

Installing GTX 780 Ti in 2010 Mac Pro