Hi,
 
I'm building following mining rig (nothing is ordered yet, I'm just puttin list of components together):
MB: ASRock H110 Pro BTC+
GPU: 6 x GTX 1070 (requires only 1 x 8 pin)
PSU: EVGA SuperNOVA 1200 P2 80+ PLATINUM (220-P2-1200-X2)
 
After reading about risers and safety issues with SATA/MOLEX versions I've decided to get these PCIE risers.
 
PSU has 6 GPU slots and following cables:
2 x 6+2pin + 6pin PCI-E VGA Cables
4 x 6+2pin PCI-E VGA Cables
 
Q1: Can I use 6+2pin + 6pin to power 1 GPU and 1 riser? 6+2pin to the GPU and 6pin to the riser. Is it ok if GPU and riser are powered from the same cable?
 
Q2: If yes, can I use extender on the 6 pin, because it's going to be too short to reach riser. Won't there be same problems as there are when people are not connecting risers directly to the PSU but use SATA/MOLEX adapters?
Can you recommend which extender should I buy?
 
Q3: I already own EVGA SuperNOVA 650W P2, bought in ~2015. This PSU also has 2 x 6+2pin + 6pin PCI-E VGA Cables. Can I use these and connect them to the 1200W version?
Are 6+2 pin + 6 pin from 650W and 1200W of same quality? Aren't cables from 650W somehow weaker? If yes, this gives me 4 x 6+2pin + 6pin PCI-E VGA Cables so I can power 4 GPUs and 4 risers.
 
Q4: Can I get remaining 6+2pin + 6pin from EVGA after registering my PSUs? Do they send/sell them to the European (Slovakia) customers?
 
Q5: If not, can I split 6+2pin into 6+2pin + 6pin (creating 6+2pin + 6pin cable)? If yes, can you recommend what do I need to buy?

Thanks you very much for any help.

Hi, thanks for answer.
 
Q1: What I meant was, is it safe to power 1 GPU and 1 riser with the same original EVGA cable that is bundled with the PSU? Will it not overload? 
Q2: I wanted to power everything from just 1 PSU. Ideally I would use 6 x 6+2pin + 6pin PCI-E VGA Cables. 1 cable for 1 GPU (6+2pin) and 1 riser (6pin). 
 
Can I use CableMod ModFlex™ 6-pin PCI-e Extension 45cm to extend 6pin on the 6+2pin + 6pin cable? 
 
650W is used in my computer, I don't plan to use it for mining. If I were to use 2 PSU for mining, I would buy 2 new PSUs (850W?).
 
Thanks.