So I have 3x SATA cables/branches with 3x SATA connectors on each. I attached 2x GPUs (which are on 16x USB risers with molex connectors. These risers have molex to sata extenders ) per branch so I dont overload a single branch (3rd SATA connector on each branch is not attached to anything, except one on which I plugged the SSD with nvOC on it). One branch with molex connectors is plugged into the two molex slots on MB.
Alright having 2x per SATA is a good rule thumb. How much power draw per card? And how much from the wall?
1050tis use 68 watts + from the riser; even 1 sata per riser will most likely not be stable:
with 1050tis you need to use pcie 6 pin powered risers and plug the 6 pin pcie cable directly into the riser.
If you are using molex risers one per cable (from the psu to directly plugged into the riser) might be ok; but you really want to use the 6 pin pcie for these.