6 GPUs on mobo MSI Z77A-G45

[RickJamesBTC]

I've got three of them. Tried it on all three. Each has a celeron G1610, 4gb ram, xubuntu 12.10 or 13.04 (also tried bamt 1.3) running from usb drives. Cards on risers, because you can only run three cards on the motherboard without risers. Risers and gpus are all known good. The boards just don't boot when I have more than three cards plugged in.

Pop in another stick of ram, for 8GB.  Now that you mention it, I was never able to run more than 3 cards with 4GB either.

Tried that, also monitoring through htop. Never even gets close to using 4gb of ram, and that wouldn't matter on boot. The motherboards won't even start.

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[Gazza1]

Weird.  I've got a few of those boards running 6 cards each.  RAM usage never goes above 4, but the system allocates 7.9GB with 6 cards if you watch with RAMmap or an in depth ram watcher.

[RickJamesBTC]

Weird.  I've got a few of those boards running 6 cards each.  RAM usage never goes above 4, but the system allocates 7.9GB with 6 cards if you watch with RAMmap or an in depth ram watcher.

None of my other rigs with 5-6 cards use more than 2-3 gb (none of them have more than 4gb installed). I've never had one of these msi boards start up with more than 3 cards plugged in, so I can't monitor that.

It's not a big deal, I took them out of the racks and they just run their three cards in the pc case and heat up my downstairs rooms.

[Gazza1]

I assume you're monitoring with a program other than taskmanager?  Because task manager doesn't show it.

Which cards are you using on the other rigs? 

[RickJamesBTC]

htop, I'm running linux not windows.

[jch9678]

RickJamesBTC, did you ever try running windows to see if that works.  Just curious because I may be in the same situation as you except I'm running windows 8.1 with 8GB of Ram.  I just bought 2 of your usb risers to test and they get delivered today.  At least I know your risers worked for you. 

Someone told me he had trouble with some long ribbon risers and 290s.  My 8x-16x risers work, they are ~17cm and have 2 capacitors but my 1x-16x risers are 30cm and have only 1 capacitor.  I thought the extra capacitor might be reducing the extra 'noise' the 290s introduce (speculation) or the length could be the problem?  Although all the risers work just fine on a test motherboard.  Very weird.  I had to order the long USB risers from you because that was all that was left in stock, has anyone reported trouble with the risers due to length? 

Long shot, but do you run a Corsair AX1200 or an Antec HCG 900?  I noticed in your thread about the risers someone was having trouble with that Corsair.

Gazza1, is this the modified driver you are talking about?  https://litecointalk.org/index.php?topic=11761.0

[RickJamesBTC]

The USB risers work at quite a long length. I've got some on 10' cables. Some on 6' cables. All work fine.

I have no interest in running windows on my machines. I have far too many rigs to bother with those installations.

Power supply has zero effect on the performance of cards, as long as there is enough power available for your system it will be fine.

Thanks

[jch9678]

Ah good to hear. 

I was thinking the power supply may have an effect on the risers using the molex connection.  I'm just speculating about my problem. 

Looking forward to trying your risers.

[tsg]

jch9678 I'm using 3x 1x1 risers (19,5cm), 1 riser 16x16 (19,2 cm. Riser 16x16 is needed in the middle 16x slot) and 2 risers 1x1 (30cm)

Slots:
-1 (1x1)
-2 (1x1)
-3 (1x1)
-4 (empty)
-5 (16x16)
-6 (1x1)
-7 (1x1)

Show us picture.  That makes sense though, the x16 providing the presence needed on that slot.  Very interesting.    I bet a x4 would work too then.

6 gpus are possible and not really hard. I've just built another rig on that motherboard (6x r9 270x).

The key is Linux and using 16x16 riser (Maybe x4 would work too, but I had only x16 )