Multi GPU on win 7 help needed

[Charloz24]

Short story: I have 2 rig:

rig 1: two 280x and one 370, works perfect

rig 2 : three 370, works perfect

I ordered some more 370, (want to run rig 1 and rig 2 5 gpu each), so in waiting time I was looking to put two 370 that are on rig 2 on rig rig to test it.

Problem is, I'm unable to let windows detect more than 3 gpu, is that a driver problem?

I was thinking it's 6+ gpu that need special driver?

TIA

EDIT: OS is windows 7 64 bits

[YellowMoon]

Which motherboard do you use? For some mothboards, if you use the x1 riser, you need to short the A1B17 or B1A17 card presence pin.

[Charloz24]

Which motherboard do you use? For some mothboards, if you use the x1 riser, you need to short the A1B17 or B1A17 card presence pin.

MSI P67a-GD65

where is that pin located?

[joblo]

Which motherboard do you use? For some mothboards, if you use the x1 riser, you need to short the A1B17 or B1A17 card presence pin.

MSI P67a-GD65

where is that pin located?

Shorting out the pins just tells the motherboard to provide 75W to the slot, usually x1 is limited to 25W.
It may result in more power going through the MB than it can handle. I don't recommend it.

Make sure you use powered risers. With powered risers the power from the slot is not used. My rule of thumb
is the MB is designed to supply enough power to as many GPUs as there are x16 slots. Any more GPUs than
that and extra power is needed.

[Patusinmod]

Which motherboard do you use? For some mothboards, if you use the x1 riser, you need to short the A1B17 or B1A17 card presence pin.

MSI P67a-GD65

where is that pin located?

Shorting out the pins just tells the motherboard to provide 75W to the slot, usually x1 is limited to 25W.
It may result in more power going through the MB than it can handle. I don't recommend it.

Make sure you use powered risers. With powered risers the power from the slot is not used. My rule of thumb
is the MB is designed to supply enough power to as many GPUs as there are x16 slots. Any more GPUs than
that and extra power is needed.

If you use powered risers, there should be no problem.

[Charloz24]

Yes powered riser, just one non powered and was on x16 slot.

[Vaccomondus]

try to add one at time not all at once

[Charloz24]

try to add one at time not all at once

Tried that too... still no work. I'm testing the same thing on a gigabyte p67a ds-3, and it's the same thing, 3 gpu ok, but 4+ not recognized (code 28). It is a chipset thing?

[joblo]

try to add one at time not all at once

Tried that too... still no work. I'm testing the same thing on a gigabyte p67a ds-3, and it's the same thing, 3 gpu ok, but 4+ not recognized (code 28). It is a chipset thing?

What exactly happens? Does is start to boot Windows? Does it succeed? How many cards?

If it doesn't get past the bios it's probably an underpowered PSU.

[Charloz24]

try to add one at time not all at once

Tried that too... still no work. I'm testing the same thing on a gigabyte p67a ds-3, and it's the same thing, 3 gpu ok, but 4+ not recognized (code 28). It is a chipset thing?

What exactly happens? Does is start to boot Windows? Does it succeed? How many cards?

If it doesn't get past the bios it's probably an underpowered PSU.

With 4+ GPU it boot ok to windows, but there is just 3 gpu recognized. Power supply is a very good 850w and R7 370 aren't power hungry. I'm thinking there is something with P67 chipset, because 2 different board (msi, gigabyte) and it's the same. Anything plugged in the two pci-e x1 between those pcie x16 aren't recognized by windows 7 and I also tried windows 8.1

[joblo]

try to add one at time not all at once

Tried that too... still no work. I'm testing the same thing on a gigabyte p67a ds-3, and it's the same thing, 3 gpu ok, but 4+ not recognized (code 28). It is a chipset thing?

What exactly happens? Does is start to boot Windows? Does it succeed? How many cards?

If it doesn't get past the bios it's probably an underpowered PSU.

With 4+ GPU it boot ok to windows, but there is just 3 gpu recognized. Power supply is a very good 850w and R7 370 aren't power hungry. I'm thinking there is something with P67 chipset, because 2 different board (msi, gigabyte) and it's the same. Anything plugged in the two pci-e x1 between those pcie x16 aren't recognized by windows 7 and I also tried windows 8.1

It could be Windows refusing to recognize a GPU in the x1 slot without shorting the pins previously mentioned. You can google
to find the procedure. I'm not familiar with Radeon so it could also be a driver issue, make sure you're using the same driver
version as your good rigs.

[Ayers]

try to add one at time not all at once

Tried that too... still no work. I'm testing the same thing on a gigabyte p67a ds-3, and it's the same thing, 3 gpu ok, but 4+ not recognized (code 28). It is a chipset thing?

try to upgrade the motherboard chipset with the last version, if this is not working it's probably the motherboard, you need something more valuable liek the h81 pro btc

[Charloz24]

try to add one at time not all at once

Tried that too... still no work. I'm testing the same thing on a gigabyte p67a ds-3, and it's the same thing, 3 gpu ok, but 4+ not recognized (code 28). It is a chipset thing?

What exactly happens? Does is start to boot Windows? Does it succeed? How many cards?

If it doesn't get past the bios it's probably an underpowered PSU.

With 4+ GPU it boot ok to windows, but there is just 3 gpu recognized. Power supply is a very good 850w and R7 370 aren't power hungry. I'm thinking there is something with P67 chipset, because 2 different board (msi, gigabyte) and it's the same. Anything plugged in the two pci-e x1 between those pcie x16 aren't recognized by windows 7 and I also tried windows 8.1

It could be Windows refusing to recognize a GPU in the x1 slot without shorting the pins previously mentioned. You can google
to find the procedure. I'm not familiar with Radeon so it could also be a driver issue, make sure you're using the same driver
version as your good rigs.

YES! Finally worked with 4XGPU with the wire trick, should have done it first... now let try 5.

Thanks everybody!

[Charloz24]

And it worked for the 5th card too, but this last one needed the 6GPU+ mod.

[joblo]

And it worked for the 5th card too, but this last one needed the 6GPU+ mod.

Glad it worked out for you. I have an old pentium on Win7 that does not have this problem.
Maybe the board already had x1 high power enabled.

It's typical Microsoft behaviour, sticking its nose somewhere it doesn't belong. It's should be
purely a hardware issue controlled by the MB. If the MB can't handle the additional power, then
display a message or generate an appropriate beep code. If the BIOS doesn't complain, neither
should the OS.

end rant

[Bazelak]

And it worked for the 5th card too, but this last one needed the 6GPU+ mod.

Glad it worked out for you. I have an old pentium on Win7 that does not have this problem.
Maybe the board already had x1 high power enabled.

It's typical Microsoft behaviour, sticking its nose somewhere it doesn't belong. It's should be
purely a hardware issue controlled by the MB. If the MB can't handle the additional power, then
display a message or generate an appropriate beep code. If the BIOS doesn't complain, neither
should the OS.

end rant

I do not think the MS will have test the current output or the requirement of the motherboard. I never heard about it.

[joblo]

And it worked for the 5th card too, but this last one needed the 6GPU+ mod.

Glad it worked out for you. I have an old pentium on Win7 that does not have this problem.
Maybe the board already had x1 high power enabled.

It's typical Microsoft behaviour, sticking its nose somewhere it doesn't belong. It's should be
purely a hardware issue controlled by the MB. If the MB can't handle the additional power, then
display a message or generate an appropriate beep code. If the BIOS doesn't complain, neither
should the OS.

end rant

I do not think the MS will have test the current output or the requirement of the motherboard. I never heard about it.

Maybe you're right. The bios may have done it and shorting the pins may have passed the bios check. I that case I would
expect the bios would error and enter setup rather than disabling the slot and proceeding to boot.