The graphics cards won't be drawing from the PCIe Riser as long as you have the PCI-E connected directly to the video card. My rigs run just fine on SATA power connectors directly to the Riser.
6 GTX 1070 + MB + CPU + RAM + SSD = 75 watts idle and 860 watts at full hashing load (cards set to 90% power). I run that 860 load on a single 1000 watt PS
OK ill order these cables that Vann has already suggested
https://www.aliexpress.com/item/10Pcs-Set-Dual-Molex-4-Pin-To-One-PCI-E-6-Pin-Power-Connector-Y-Adapter/32820421116.htmlAlright here is my buy list again. If there are no more suggestions or problems I will order it:
ASUS B250 MINING EXPERT
$181.99
DREVO X1 120GB 2.5 Inch SSD SATA III Internal Solid State Drive
$69.99
Ballistix Sport LT 4GB Single DDR4 RAM
$59.99
Intel Celeron G3900
$53.99
Gigabyte GV-N1070WF2OC-8GD Gtx 1070
8x $513.50
EVGA G2 850W
2x $176.9
PCIE Risers
Dual Molex to 6 Pin PCIE
PC power switch