Hey guys and gals, hope everyone is having a great day. So I ordered everything to get my first mining rig and have a question. I have a ASRock H81 PRO BTC R2.0 motherboard and (2) MSI 480 gaming x GPUs. I know the board has a molex connector to help power the pci ports, but my question is do I need to power all the risers and use the molex on the board or just use the powered risers by themselves?
Thanks in advance!
Yes you must use Both for that motherhood
Thanks stealth for the quick response! Appreciate it.
Board has two extra power connections that’s needed and it’s fully explained with motherboard instructions
Your welcome welcome to mining,want be long before you fill up that board with cards lol rx480 as best for zcash good chose
Thanks, yea I really only got into mining like month and a half ago. Started with burst and then found out about Zcash and having been mining it on my gaming computer, but wanted more. Mining is addictive! I can’t wait to get some more cards when funds work out.
I’d recommend non-powered risers with that motherboard since if you are plugging in the Molex to the motherboard then you’re good. Adding powered risers to that can be asking for trouble as you may inadvertently put too much power on the PCI-e bus.
So many noobs use USB risers on that MOBO with the molex connector plugged in to the motherboard which is wrong.
Either use the PCI-e powered risers and DON’T plug the molex into the motherboard or use regular risers with it and plug the molex into the motherboard but doing both is dangerous.
To see how wrong this is, note that ASRock actually makes a riser for this board that does not include a power connector.
https://www.amazon.com/ASRock-Cable-BTC-PRO-KIT/dp/B00ITG1ZWY
I run powered raisers + molex just fine on that board. 
Just make sure, when you use 2 PSUs, that all powered raisers are connected to the same PSU that supports the mainboard.
Its all fun until you burn out a card or the board itself. You’ll learn eventually.
Ok, thank you cascadia. That is what I was worried about. Makes sense to use either riser power or the molex power on the board.
You’re welcome. I hate seeing people get wrecked or burn out their cards. A burnt out GPU is a sad thing to behold.
Yes I’ve seen 2 cases of that before. 
I’m not sure how using powered risers and molex connectors could be dangerous.
The card will only draw as much current as it needs. You can’t over power it.
You’d actually be splitting the load across two separate cables therefore decreasing current draw across a single cable, which would actually be safer than drawing the current across one.
That was my thought aswell.
The cases with molten cables + GPUs which I have seen were referred to mixing the powered raisers across 2 PSUs.
Just so you know I’m talking about using powered risers while also powering the molex connector mounted on the surface of this particular motherboard which is used for essentially the same purpose as the powered risers. Too much power on the PCI-e bus is dangerous.
Which does not make sense. You dont put in “more” power by just connecting the cables. You just give the hardware more supply if it needs to draw more power which could be delivere through the molex connector only.
If the draw is higher than the supply, you melt the cables.
There is no such thing as putting too much power on the PCI-e bus. It would be the same as using either a 500w psu for instance or using a 1500w psu. It’s too much current draw that would cause damage.
Yes.
Here is a nice case of molten connectors.
https://forum.ethereum.org/discussion/7367/using-an-asrock-h81-pro-btc-board-beware
Just mainboard molex power supply for 6 cards might not be strong enough.
Exactly the case! Load should be split across the molex and the PCI-E