GA-970A-UD3 will not take more than 3 cards

[Velocd]

I am having trouble getting my motherboard to see more than 3 cards.  All cards and risers are working properly and I can get 3 recognized and stable while mining but adding a 4th card starts to cause issues. Most of the time it will not recognize it. Other time it will turn the fan up on the 4th card to 100%. Other times it will cause my third card to not be recognized.  I have updated to the latest bios and still have the same issue. I have 2x 280x and 2x270 both gigabyte. The 280x cards are on 16x risers and the 270s are on 1x to 16x risers. 

The only slots I am able to get cards to come up on are the first pcie 1x and the 2 16x slots.  If I plug the 1x riser into any other 1x slot I will get the odd issues I stated above and if I plug a 4th card into any of the other spare 1x slots I also get the same odd issues.  I am hoping there is something in the bios that I am missing but I have dug around and nothing really pops out. 

Pic of the mobo
http://www.gigabyte.us/fileupload/product/2/3907/4462_m.jpg

[Flashman]

Check the specs to see how many channels are available total, some boards only have 16x (shared) plus an extra 1x, thus if the full length ones claim 8x each then there's only 1x left.

[Velocd]

Would the manual have that kind of info. Also of that is the case could I use 3 1x to 16x and 1 16x riser to get 4 cards going?

[Velocd]

Just moved my 2nd 280x from the pcie 4x slot with a 16x riser to a 1x slot on a 1x to 16x riser and installed the jumped and that actually worked.  Is there a way to mod my 16x to 16x riser to make it 1x to 16x?  Otherwise I will need to buy another 1x to 16x to test this theory.

[Flashman]

You can tape over the presence detect pins to see if that will work, should do if all those cards are identical, since one is working on 1x already, if different model, it can be the case that the 1x 4x etc pins aren't connected on the GPU PCB so you have to link the presence detect and signal pin to force it.

Pinout of slot...
http://pinouts.ru/Slots/pci_express_pinout.shtml

The relevant prsnt#2 pin is connected to the prsnt#1 pin, so preventing contact on the 16x 4x prsnt#2 pins should force 1x (That's not the best pinout diagram I've ever seen but extended googling may bring you something better)


Edit: Better info... http://framer99.blogspot.ca/2013/11/multi-gpu-machines-and-pcie-in-band-vs.html

[Velocd]

yeah I got the jumpers on the pcie 1x slots and thats working, but I don't have another 1x to 16x riser. Just a 16x to 16x.  Is it possible to mod the 16x to 16x down so that it can fit into the last 1x slot on my mobo?

[Flashman]

Ohhh that way round.

Yes, if you really really want to cut that or to trim the back out of the PCIe 1x slot on the motherboard very carefully so that it hangs out of the back (Check clearance behind slot) that can work. I have modded PCIe 1x slots very carefully with small sidecutters, the trick is to just nibble a bit at a time. However, you can mangle the last couple of pins accidentally, likewise if you're not careful with the 16x edge connector you can tear the adjoining pad when you cut it. probably best to aim a half pin over then file it with a fine file.

[Velocd]

Yeah I was thinking to just give it a go with a dremel and diamond blade on the 16x to 16x riser.  If I mess it up I am back to square 1 of having to buy one.  I don't really want to do that to the mobo.  I don't need to fully cut the riser right, just notch it so it goes into the slot?

[Velocd]

So someone over in the litecoin mining subreddit suggested disabling the USB 3.0 controllers.  The sporadic boot issues are gone. The computer now boots with all 4 cards acting normally but the OS is still only seeing 3 cards. Anyone have any ideas as to what I should try next?

[abshnasko]

I have the same issue with my UD7 running BAMT. Disabling USB 3.0 didn't work for me. BAMT "sees" all 4 of my cards, but cgminer won't boot and I get kernel panics.

[Velocd]

Yeah I'm chalking it up to gigabyte doing something shady with the pcie channels. Oh well. At this point I'm considering either returning the 270s for another 280x or just stick with a 2 280x's and 1 270. No loss really. Converted my desktop pc to a miner

[indeskyz]

This really worries me because I had planned to buy a GA-970-UD3 tonight along with 3xR9 280x's in combination with 2x290x's I already have. Are you using powered risers or just normal?

[altcoinex]

For my own curiosity, are the 1x to 16x risers unpowered or powered?

[Velocd]

Powered risers. Here is an interesting reply from someone on the litecoin mining sub redditt out the board

[–]TehGogglesDoNothing 1 point 10 hours ago
I looked up the manual for your computer. The 16x PCIe, all 3 1x PCIe, and the NIC all share the same bus. The x4 PCIe is on its own bus. You might want to try putting one card in the x4 slot and the other three in x1 slots.

[abshnasko]

I'm using powered risers and I've tried all manner of slot combinations. I can't get anything to work. I'm changing my hardware setup now...

[Velocd]

Powered risers. Here is an interesting reply from someone on the litecoin mining sub redditt out the board

[–]TehGogglesDoNothing 1 point 10 hours ago
I looked up the manual for your computer. The 16x PCIe, all 3 1x PCIe, and the NIC all share the same bus. The x4 PCIe is on its own bus. You might want to try putting one card in the x4 slot and the other three in x1 slots.

So using the 4x slot and the 3 1x slots does not work either. This board must not support 4 card. Looks like I am returning a 270.

[abshnasko]

I can't get it to work with 2x 7990s either, so I guess it can't handle four GPUs, though it says it does 4-way crossfire. What a piece of shit.

[diond]

I just bought the GA-990FXA-UD3, that's supposed to handle up to 6 cards, along with (3x) R9 280X Asus Cards about a week ago. I'm also using powered 1x to 16x risers for all my cards. I'm also getting total inconsistency with the slots. Switching my 1x to 16x risers to varrying slots creates all kinds of problems with my hash rates.

I just got my 4th R9 280X Asus card in today and will test having 4 cards on the mobo tomorrow... hope I don't get more crap. If I do get more crap, I'll try putting 3 cards directly on the mobo without the risers to see if I get better results.

I may just have to go back to good ol Asus motherboards ... their cards are definitely top notch performers.

Thanks for the posts!


PS: I had bought a GA-990FXA-UD5 about 2 weeks earlier and had the first PCIE16_1 slot completely dead and had to return the mobo. I'm thinking Gigabyte may be crap in regards to consistent performance.

[Flashman]

I invariably end up referring to any gigabyte hardware that crosses my bench as the gigabytch...

I got badly burned back in the day on a board they released with a bad AGP stability problem*, so never acquire any of their stuff intentionally.

(*If you wonder how that can be, well it took independant hardware hackers to demonstrate it before they admitted it, about 15 months after the release of the board, meanwhile denying the problem... so poor saps like me with a flakey rig were replacing PSUs, RAM, AGP cards multiple times...)

Anyhoo, it makes them very hard to trust.