I have Chieftec Navitas 1000W PSU that has only 2 common GPU outputs
http://www.chieftec.eu/en/psus/navitas-serie/gpm-1000c.html

I want to connect additional GPUs via molex but with PSU I got only 1 such cable. And I couldn't find anywhere CHieftec spare cables.
So I've purchased CorsAir Individually Sleeved DC Cable Kit
http://www.corsair.com/en/professional-individually-sleeved-dc-cable-kit-type-3-generation-2-red

GPU get both green lights, turns coolers but neither BAMT nor Ubuntu recognise the card on which I try them, I've tried card restart with cables, doesnt work, but the power doesn't seem to be an issue?

How can I trouble shoot the issue?

GPUs are Asus R9 270x DCII Top OC