Help, ASRock H81 Pro BTC with more than 2 GPUs

[techstorm3]

Hi All


Just got a asrock H81 ProBTC Mobo and have 2 R9 270X with 1350 watt PSU running ok, the mobo has 1 x16 and 5 x1, ive tried adding a 3rd 270X and the existing 2 work ok but the fans wont spin on the 2rd one, any ideas?


I know the 2rd 270X works as it came out of a working rig and Ive put it back in this other rig and it works fine, just wont work in the new rig, the Pro BTC is supposed to run 6 GPUs potentially (not that I'll be doing that), 3 would be nice.

any help would be much apreciated.

[Molex1701]

Did you plug Molex's into the extra Molex sockets on the motherboard?  They are there to provide extra power for cards.

[SneakyNinjA]

I have 5 GPU's running on my H81, all out of powered risers on the 1x slots. I've been playing with the x16 slot on my other build, but for some reason i get some problems when i touch the x16 slot.

[Nastrond]

Any luck on this today? Same board, same cards, same problem. Hard to find enough info on this online. Had 3 working ok. Put in the 4th and it wouldn't detect. While troubleshooting, somehow I lost the 3rd and now only two cards detect. The cards all work fine

edit: now the 3rd card is showing up again by switching pcie slots

My specs are:

win7
asrock h81
msi 270x
thermaltake 1475w

Only enough power connectors to power 4 cards for now (even with molex adapters).. still trying to resolve this some how to get to 5 or 6. Thermaltake's parts store does sell any wires for this particular PSU for some terrible reason.

[SneakyNinjA]

I would suggest getting a voltmeter, you could be plugged into the same rails on your PSU and therefore attempting to draw too much voltage despite having the watt rating. (I'm not an electrical engineer though)

I've had a lot of issues with 1500 watt PSU's and have since switched to using multiple 800-1000 watt psu's.

[notlist3d]

I am working on a official review of this motherboard.  Lets just say it has not went well.... I have been asking them questions through email seeing their claims vs actual performance.   I am waiting on a few more emails before I do it.   I asked if I could include their emails in my review .... I have a feeling that request will be turned down. 

[AndrewGucci]

I am working on a official review of this motherboard.  Lets just say it has not went well.... I have been asking them questions through email seeing their claims vs actual performance.   I am waiting on a few more emails before I do it.   I asked if I could include their emails in my review .... I have a feeling that request will be turned down. 

Where will be that review ?

[BTCIRV]

I started having these issues in windows when I tried to change a simple setting. Everything went haywire and cost me 36 hours. I switched to SMOS BAMT and all seems to be running just fine, but only with 5 cards.

I've not tried the 6th yet.

otherwise the board seems fine. It may be a driver issue and not the board. Others are reporting similar problems on different boards.

[johncarpe64]

Did you plug Molex's into the extra Molex sockets on the motherboard?  They are there to provide extra power for cards.

But the problem is 1x doesn't supply enough power to GPU..

[Mineraholic]

I have several rigs using this board and I can tell that every board behaves different.
After installing my first rig using 5 R9 280X, 1 Corsair 1000W and 1 750W psu, I assumed that I could easily finish the rest because they're identical.
But unfortunately not.
First rig with normal setup with power to the board. Second rig needed power from both psu, each psu to the board.
Third won't work unless there is no molex to the board!
4 rigs up and running each setup different and now I am facing some different issue on no.5 and still can't resolve it. Nothing seems logical.

So in short, it is a pain in the ass to get it all working with this motherboard. I suspect the motherboard is to blame.
I never had this problem when I used Gigabyte motherboard, but they are more than twice as expensive.
But don't buy Gigabyte because they won't work with BAMT. There is a solution, but that's another story.

Try different setups using different pci-e ports, try using 1 molex to the board, try none, etc. Some combinations just won't work.
Which psu do you got? Is it a single rail? Go through everything and try some crazy illogical stuff too.
You should be able to plug 4 R9 270X on your psu with undervoltage. 3 cards should be under 900W.

Good luck!

[thenextmoney]

Has anyone else had the h81 pro btc explode on them when plugging in the additional molex's?