I can not make 2 differnt AMD cards work in one machine

[ChrisD5710]

Just bought a new RX 5500 XT card to improve my Folding Power.

My machine already has one HD 7970 GHz Edition graphics card.

Now it seems that I can not make these 2 cards work together.

When I place these 2 cards in one machine, I do not get any video from any of the 2 cards. One card at a time, no problems, but both cards, no video.
It makes no difference, which card I place in which slot.

Newest drivers installed, of course

Ideas anyone?

ChrisD5710

[Neil-B]

I'm not a GPU person but I'll throw in "have you got a good enough power supply?" … Also one is PCIe 4.0 x8 and the other PCIe 3.0 x16 - "Is your MoBo up to driving both of these at once?"

[Sven]

Is your motherboard's BIOS update to date?

That helps sometimes with 2 video cards.

[muziqaz]

Chris, I have Vega64 which tried and liked a pint of beer. I did not think Vega64 will like that beer so went and bought 5700xt. So when I found out that Vega64 Liquid Edition is beer compatible, I ended up with two GPUs.
When I placed Vega64 in primary PCie4-x16 slot, and 5700xt in secondary PCIe4-x4 slot, 5700xt was not working, was heating up, but not working.
When I put 5700xt in primary pcie4-x16 slot and vega64 into secondary pcie4-x4 slot they work.
In BIOS I had to specify in what mode both PCIe slots should be working, as Auto mode for some reason would freak out and that would mess up everything.
So primary slot I set specifically for pcie4-x16, since 5700xt supports pcie4, and secondary slot I specifically set up as pcie3x4, since vega64 does not support pcie4.
Some motherboards have physical switch on motherboard to enable multiGPU set up. Check the manual. And sometimes there is an option in the BIOS to enable multiGPU.

It would be helpful if we could get all the info on your full hardware set up, and bios version:
motherboard name, model, bios version (update bios to latest will not hurt, as Sven suggested)
CPU name, model, and is it overclocked
PSU name, model wattage

I take it you connected pcie power supply to both cards. Keep in mind some PSUs even though have enough wattage to supply two GPUs, they might have separate 12v rails, so both GPUs need to have separate pci-e power cables coming from PSU. Some PSU have these Y split cables, so that one cable coming from PSU supplies 4x 8pins. best practice is always to have one cable supply one card, and another separate cable another card.
Some motherboards have molex plug next to one of the pcie slots to supply extra current to pcie slots.

[Joe_H]

With two cards the far apart in generations you may be running into issues of driver support. Check to see what driver version fully supports the HD 7970 with both video and OpenCL. That may be too old to also support the 5500 XT.

AMD has not been including OpenCL support in some of the newest drivers to support older cards, just video drivers. Finding the exact cutoff points for various cards is not easy, I have not found a single resource that lists this information.

[muziqaz]

With two cards the far apart in generations you may be running into issues of driver support. Check to see what driver version fully supports the HD 7970 with both video and OpenCL. That may be too old to also support the 5500 XT.

AMD has not been including OpenCL support in some of the newest drivers to support older cards, just video drivers. Finding the exact cutoff points for various cards is not easy, I have not found a single resource that lists this information.

He is experiencing issues way before he hits Windows.
His cards refuse to work before POST.
Latest AMD driver still supports 7970

[Joe_H]

Latest AMD driver still supports 7970

for video acceleration, does it also include support for the OpenCL runtime? The 7970 is a GCN 1st gen. card and only supports OpenCL 1.2. AMD has been removing parts of the support for the early gen GCN cards in the latest drivers and leaving in only the video acceleration.

[muziqaz]

7970 lived as 100 other later released cards, due to AMDs renaming policies, so if they are cutting opencl support for 7970, they are cutting a lot of R9/7/5 200 series cards.

[paulmd199]

The HD7970 can draw up to 250 Watts and the RX 5500 XT can draw up to 150. Have you got a power supply that's capable of that, plus about another hundred for the processor and a bit more for the rest of your components? I'd say 600W (which is a lowball estimate) or higher.


Source:
https://en.wikipedia.org/wiki/List_of_A ... sing_units

[Joe_H]

7970 lived as 100 other later released cards, due to AMDs renaming policies, so if they are cutting opencl support for 7970, they are cutting a lot of R9/7/5 200 series cards.

The Tahiti chip variants from the 7970 were used in a total of 19 cards, the most recent released 6 1/2 years ago. Other GCN 1 chips were involved in some of those other series, AMD has been reducing OpenCL support for GCN 1 and Terascale based cards over the last couple years. They can still be used, but often only if a prior version driver is loaded. That may just require going back to drivers released late last year, but for some of the cards it means going back further.

[muziqaz]

7970 lived as 100 other later released cards, due to AMDs renaming policies, so if they are cutting opencl support for 7970, they are cutting a lot of R9/7/5 200 series cards.

The Tahiti chip variants from the 7970 were used in a total of 19 cards, the most recent released 6 1/2 years ago. Other GCN 1 chips were involved in some of those other series, AMD has been reducing OpenCL support for GCN 1 and Terascale based cards over the last couple years. They can still be used, but often only if a prior version driver is loaded. That may just require going back to drivers released late last year, but for some of the cards it means going back further.

Possible, has it been witnessed that 7970 with latest drivers is not able to fold?
I have some 100 times renamed passively cooled HD230 series card, which I assume is from same family as Tahiti, but that one required some 3 year old drivers to even work in Windows, so I cannot test

[Joe_H]

R5 230 series cards? Those would be based on Terascale 2, even older that the GCN 1 Tahiti. There were several GCN 1 chips besides the Tahiti - Oland, Picairn, Cape Verde and so on.

[muziqaz]

R5 230 series cards? Those would be based on Terascale 2, even older that the GCN 1 Tahiti. There were several GCN 1 chips besides the Tahiti - Oland, Picairn, Cape Verde and so on.

You are correct.
Boy, was I undersold with that product
Just joking, just needed back up GPU to be able to display something to monitor when main GPUs died, or drank beer

[ChrisD5710]

Hello All

At first, Thanks for all Your answers I will try to answer some of the questions that pop up:

first this:

The HD7970 can draw up to 250 Watts and the RX 5500 XT can draw up to 150. Have you got a power supply that's capable of that, plus about another hundred for the processor and a bit more for the rest of your components? I'd say 600W (which is a lowball estimate) or higher.

Source:
https://en.wikipedia.org/wiki/List_of_A ... sing_units

PS Unit is a Corsair HX 850, so there should be ample power.

CPU is a Xeon 12 core model with a C602 Motherboard to go with it, so there should be plenty of pci lanes.

Drivers are the latest AMD drivers and I have one machine with 2 x 7970 and they just work fine. In this machine each card will run if installed alone.

I have no manual for the BIOS but I will find a time to stop folding and examine the BIOS settings to see if one adapter can be selected over another.

You are right, these two cards are many generations apart, but I can not get myself to ditch the 7970. It still does a decent amount of Folding.

Again, Thank You all for Your help.

ChrisD5710

[Neil-B]

Not sure about the PCIe lanes on a C602 based Mobo … https://ark.intel.com/content/www/us/en ... ipset.html