The danger to GPU miners comes from use of graphics cards that only require 2 x 6 pin PCI-e connectors from the power supply.  The 2 x 6 pin PCI-e connectors only provide a maximum of 200W from the PSU, leaving the rest to be provided by the motherboard.  Cards such as certain models of the HD 7950, only require 2 x 6 pin PCI-e connectors but could potentially pull up to 225W total, leaving 25W to be provided by the motherboard.  If the card is connected to a PCI-e 16x lane with 75W available throughput, then there is no problem; however, if the card is connected by an unpowered PCI-e x1 riser to a PCI-e 1x lane [max throughput of 10W] melting occurs.  ASRock has done a good job making sure that the damage won’t be at the 20+4 pin ATX connector, but the physical risers that must be used, and the soldered PCI-e 1x lanes would all be susceptible to damage.

ASRock has provided the changes to the motherboard hardware necessary to provide as much power to the motherboard as is needed to power 6 GPUs; however, the use of PCI-e 1x lanes again necessitates the use of powered PCI-e risers, which negates the ASRock H81 Pro BTC’s only advantage.  Given the fact that the H81 Pro BTC only has 1 PCI-e 16x lane and 5 PCI-e x1 lanes, users will still run into significant power issues the majority of the time if they try to take advantage of all the motherboard tries to offer for GPU mining.

The Butterfly Monarch (BFL) PCI-e card, scheduled for 2014 delivery, would also be a poor match for this motherboard.  Even assuming that BFL makes their target power consumption of 350W it would be impossible to get 6 Monarchs on one motherboard without having two prohibitively expensive power supplies as well as the necessity for powered risers.  There are dozens of better motherboards [better in this instance means PCI-e 16x lanes instead of PCI-e 1x lanes] for mining.