Trouble adding 3rd GPU

Keyo888 · Dec 11, 2013

Hey everyone, I've been torturing myself over the last few late nights trying to figure out what the problem is here.

Here are the specs:
ASrock 990fx extreme 3
2x Asus R9 290x
1x Sapphire R9 290x
EVGA 1300w PSU
Windows 7

The problem:
I can boot and run the system perfectly with 2 GPU's connected. However, the second I connect a 3rd, none of the GPUs are visible in windows and I don't get a video output signal, unless I connect my monitor to the card plugged into the pci-e2 slot (closest pci-e to the CPU).

At this point I can only think that my board is faulty and should be RMA'd.

I was pretty confident that the 3 r9 290x's even though they are different brands should be able to run no problem.

Can anyone shed some light on this?

gokul36 · Dec 11, 2013

u connected two GPU's in PCI-E2,PCI-E3 x16 mode correct?

Keyo888 · Dec 11, 2013

gokul36 :

Actually right now the 2 asus GPU's are in pci-e3 and pci-e4.

Is this not a good thing? please explain.

gokul36 · Dec 11, 2013

Install the 1st and 2nd GPU in PCI-E2,PCI-E3 at x16 mode....refer ur manual.....as x16 has high bandwidth and give full performance.....

Where PCI-E4 x4 mode Bandwidth is lower compared to x16 mode

PCI-E 2.0 X16 Bandwidth is 8000 MBs and clock Speed is 5GHz(16 bit)
PCI-E 2.0 X4 has same clock but bandwidth is lower 2000 MBs(4 bit)

gokul36 · Dec 11, 2013

to be simple...what i am trying to say is....1st fill the TWO GPU's in PCI-E 2.0 x16 (PCI-E2,PCI-E3)slot and then install 3rd GPU in PCI-E 2.0 x4(PCI-E4 x4 mode)

Keyo888 · Dec 11, 2013

Ah ok I will try that. Does this affect how my system will detect the GPUS though? The main problem I was having was the second I add the 3rd GPU ( into pcie2 the way its setup now ), the system would boot up into windows, but none of the cards would useable by my programs ( Mainly cgminer ). Also, when I check device manager for display adapters it also only showed 2 devices instead of the 3 that are attached.

If i'm understanding correctly i should:

Install 2x Asus GPUs in pcie2 and pcie3, boot up to see if the cards are detected.
Shut down, install the 3rd Sapphire GPU in pcie4, boot up and all cards should be present and active?

To clarify, I'm setting this machine up as a mining rig for crypto currencies to mess around with, so only one GPU will have a monitor plugged in, and the others will be there strictly for computing power.

gokul36 · Dec 11, 2013

Keyo888 :

Ah ok I will try that. Does this affect how my system will detect the GPUS though? The main problem I was having was the second I add the 3rd GPU ( into pcie2 the way its setup now ), the system would boot up into windows, but none of the cards would useable by my programs ( Mainly cgminer ). Also, when I check device manager for display adapters it also only showed 2 devices instead of the 3 that are attached.

If i'm understanding correctly i should:

Install 2x Asus GPUs in pcie2 and pcie3, boot up to see if the cards are detected.
Shut down, install the 3rd Sapphire GPU in pcie4, boot up and all cards should be present and active?

To clarify, I'm setting this machine up as a mining rig for crypto currencies to mess around with, so only one GPU will have a monitor plugged in, and the others will be there strictly for computing power.

yep....u understood.....

Keyo888 · Dec 11, 2013

gokul36 :

One last question, while I'm doing this, should I wipe all the AMD catalyst drivers ( currently using the 13.11 betas) and install the 2 cards -> boot up -> install drivers -> shut down -> install 3rd GPU in pcie4 -> boot up -> profit?

The AMD catalyst driver should be usable by all three cards without issue since they are all the same card, just a different brand correct?

Will report back later tonight if this worked. Thanks for the help.

gokul36 · Dec 11, 2013

dont delete the drivers....just Install ur GPU's in correct slot X16 X16 X4 k

Keyo888 · Dec 12, 2013

gokul36 :

So it turns out, when I put the 2 GPU's in pcie2 and pcie3 and boot into windows, the card in pcie2 cannot be detected and the card in pcie3 can be seen in device manager but it can't be used.

Im beginning to think the Mobo is faulty

gokul36 · Dec 12, 2013

3 GPU's u r using are same Model? same clock speed and same Memory?

Keyo888 · Dec 12, 2013

gokul36 :

They are basically exactly the same.
2 Asus 290x's
1 Sapphire 290x

Same clock speed, same memory

gokul36 · Dec 12, 2013

Maybe ur MOBO is faulty

gokul36 · Dec 12, 2013

Check ur BIOS ....if all ur PCE-I are enabled

Keyo888 · Dec 12, 2013

This is my thought as well. I'll know for sure later tonight, gonna pick up another one to test out.

Keyo888 · Dec 12, 2013

gokul36 :

I'm quite positive they are all enabled.

Check this out, not sure this really makes a difference since the cards should be backwards compatible, do you know what LSI Link Speed does though?

Regarding default settings, a couple of important points should be noted. The BIOS by default gives the PCI Express lanes as Gen 2.0, rather than a method of auto detection. Users of PCIe 3.0 graphics cards or PCIe devices should navigate to the North Bridge menu in order to set these lanes as Gen 3.0.

http://www.anandtech.com/show/6228/asrock-x79-extreme11-review-pcie-30-x16x16x16x16-and-lsi-8way-sassata/2

ASRock%20X79%20Ex11%20BIOS%2012%20-%20NB%20Config_575px.png

gokul36 · Dec 12, 2013

Try to Set everything to GEN3 or AUTO and see if it works

Keyo888 · Dec 13, 2013

gokul36 :

After rebuilding the whole system and using only one GPU, i've determined the pcie2 is faulty and the Mobo needs to be RMA'd. Out of frustration and just wanting my rig to be up and running I went out and bought a new mobo ( Asus M5a99FX pro r2.0 ). Plugged in all 3 cards and BAM. Up and running right away.

Thanks for the help.

gokul36 · Dec 13, 2013

Keyo888 :

happy! u figured out the Problem

Do u stil have warranty covered for your old Motherboard? if u have.......send it for a replacement

Trouble adding 3rd GPU

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