[.25 BTC Bounty] Cannot use more than 3 cards on GigaByte motherboard

[Boxman90]

Did it work?

[miztaziggy]

I am having very similar issues with a Gigabyte 990 UD3.

With 3 cards directly to the 3 16x slots it works fine.

With 5 cards all plugged into 1x risers, only 4 cards get detected in Windows. That is with none of the slots shorted.

The card that isn't getting detected is the card plugged into second (middle) x16 slot. Both of the others and both of the 1x slot cards get detected and mine OK.

If I short the presence mod on the 1x slots it makes no difference.


If I short any of the x16 slots with the presence mod, the motherboard WILL NOT power on at all. As soon as I pull out the shorting wire, it powers on.

I will start a separate thread here with its own bounty:
https://bitcointalk.org/index.php?topic=387663.new#new

[woutersteven]

To rule out OS or driver issues, have you tried another OS?

[dual6990s]

Powered risers?
Must have power beyond 3

[joshv06]

Did it work?

I am sorry but it did not work.

It's interesting to see miztaziggy have a similar problem.

What kind of cards are you using?

As I stated before, I have tried powered risers. No luck.

And it cannot be the OS because it doesn't even POST.

[Boxman90]

Then I'll just post the 100% guaranteed to work solution:

Change your motherboards for Gigabyte 990FXA-GD65. Use presence mod on all 4 slots in 1x unpowered risers. Don't forget the motherboard's 6pin extra PCI-e power connector.

[Boxman90]

So 'it did not work' but coincidentally the topic is suddenly dead. Don't want to pay the bounty?

[GDECOIN]

need more blower to make your machine still cool.

[rav3n_pl]

Connect on 16x16 riser to  PCIEX16_1 and  PCIEX16_2
Connect on 1x16 riser to PCIEX4_1 and PCIEX4_2
Clean and reinstall drivers.
Try connecting CF bridge to x16 cards.

[cashclash]

Odd problem indeed, do we have an answer yet?

I have the same Mobo short Risers ~ 15cm - 20cm ones do work with no problem here, i have 5 290 in one of my rigs.
I should mention that i made the powered cables myself.

Now when i use 30cm powered Risers i don't get to see a POST well sometimes it manages to show me a POST but that's it it hangs there.

It can not be a PSU problem but either cable or Mobo, i tested this with just one 290.
290 on board, works
290 on non powered 18cm Riser, works
290 on powered 18cm Riser, works
290 on powered 30cm Riser, no POST (tested with two different 30cm powered cables)

I even isolated my first self made powered risers with Aluminum Foil and on top some Isolation just to make sure i do not get interferences or magnetic fields build up but not seeing POST if i just use 1x30cm Riser cable on a Mobo with just 1 290 plugged in is pretty odd especially since my first rig is running now over a Month with 5x290 and my self made but short powered risers and yes i have been rebooting it quiet often.