Can I run a GTX card and RTX card on the same machine?

[bakayarooo]

I think I read that with Windows you can not use two cards that are not on the same DirectX. I tried to add a GTX 1080Ti and an RTX Titan in the same machine. I opened Blender and only the Titan showed up. I originally had the Titan installed and wanted to add the 1080Ti. Does Linux have the same limitation as Windows where both cards have to run the same DirectX? Has anyone tried to do this?

[SpaceGhostC2C]

12 minutes ago, bakayarooo said:

I think I read that with Windows you can not use two cards that are not on the same DirectX.

I'm not sure what you mean. You can multiple GPUs, of different manufacturers and generations, at will.

12 minutes ago, bakayarooo said:

I tried to add a GTX 1080Ti and an RTX Titan in the same machine. I opened Blender and only the Titan showed up. I originally had the Titan installed and wanted to add the 1080Ti.

That's an issue on which GPU can be used in blender. I know other programs (e.g., Solidworks) will only used the GPU hooked to the main monitor for acceleration.

 

12 minutes ago, bakayarooo said:

Does Linux have the same limitation as Windows where both cards have to run the same DirectX?

DirectX is a Windows-only graphics API.

 

12 minutes ago, bakayarooo said:

Has anyone tried to do this?

What exactly?

[RAM555789]

What do you mean by "not on the same DirectX"? Are you maybe thinking of drivers?

[bakayarooo]

39 minutes ago, SpaceGhostC2C said:

I'm not sure what you mean. You can multiple GPUs, of different manufacturers and generations, at will.

That's an issue on which GPU can be used in blender. I know other programs (e.g., Solidworks) will only used the GPU hooked to the main monitor for acceleration.

I can put 2 1080Ti's, one EVGA card and one MSI card, in the computer without an SLI bridge and blender will recognize both of them. With Blender 2.8 you can select which GPU you want to use. But when I put an RTX card and a GTX card one of them will show that the drivers are not installed. I want to know if it is because the GTX card runs on DirectX11 and the RTX card runs on DirectX12. I though the RTX card would be backwards compatible since when I play Control on my RTX 2070 it prompts me if I want to use DirectX11 or DirectX12. 

I want to know if any one has a RTX card and GTX card with both drivers installed and working on Windows and/or Linux?

 

I want to use the GTX card in addition to the RTX Titan for some Machine Learning. I will be using Linux for the ML. With Linux you can use Nvidia's NCCL drivers to direct your work load to a specific GPU even though it is not connected to a monitor.

[Sir0Tek]

1 hour ago, bakayarooo said:

I think I read that with Windows you can not use two cards that are not on the same DirectX. I tried to add a GTX 1080Ti and an RTX Titan in the same machine. I opened Blender and only the Titan showed up. I originally had the Titan installed and wanted to add the 1080Ti. Does Linux have the same limitation as Windows where both cards have to run the same DirectX? Has anyone tried to do this?

What is your special use-case? What is it you would like to achieve? Using them both for Blender to accelerate it further?

Linux doesn't have DirectX, therefore not the same restrictions. You can use more than one card, even with different drivers, but for the nvidia, both cards would have to be using the same driver-version. So far, both cards do use the same proprietary driver but that may change somewhere in the future, kicking the 1080ti out of the then current drivers down into the legacy ones. Afaik for the proprietary nvidia-driver it is not possible to use nvidia-legacy together with nvidia-current. I don't know if both cards will be actually able to work for Blender, but since it is the same driver they should indeed work. 

[SpaceGhostC2C]

14 hours ago, bakayarooo said:

I can put 2 1080Ti's, one EVGA card and one MSI card, in the computer without an SLI bridge and blender will recognize both of them. With Blender 2.8 you can select which GPU you want to use.

Which card combination is supported by Blender is Blender-specific. You need to check with Blender's documentation.

14 hours ago, bakayarooo said:

But when I put an RTX card and a GTX card one of them will show that the drivers are not installed. I want to know if it is because the GTX card runs on DirectX11 and the RTX card runs on DirectX12.

No. I had all sorts of combinations installed, like a Vega 56 and a Tesla M2070, or a Quadro FX 3800. DirectX is just a Windows graphics API and has no bearing in whether you can use two different GPUs for more general purposes.

If you don't have drivers at all for one GPU, that could be down to Nvidia offering different drivers, none of which is simultaneously compatible with both. It would be a dick move from them, but it's possible - believe it or not, it is much easier to use multiple, different cards if one is Nvidia and one is AMD than if both are Nvidia.

Having said that, have you tried downloading and installing drivers from Nvidia with both cards installed? Nvidia's web will allow you to search for compatible drivers, download older drivers, and see the compatibility of each driver. You need one with both families listed. For example, I could use the Tesla and the Quadro together but only with a specific range of drivers, which were not the newest ones. And the drivers would limit my settings for both cards to the Tesla ones, the additional settings I could access when using only the Quadro where gone when installing both.

So, it could be a driver issue, but check with Nvidia first.

 

14 hours ago, bakayarooo said:

 

I want to know if any one has a RTX card and GTX card with both drivers installed

That's the problem - I don't think Nvidia allows you to install two drivers, so you need to find one that supports both GPUs. With an AMD and an ANvidia card you would be able to install two separate drivers with no issues.

 

14 hours ago, bakayarooo said:

I want to use the GTX card in addition to the RTX Titan for some Machine Learning.

I don't think Blender does machine learning, so that's not your test  Of course, if you lack drivers for one of them, then that's your number one problem. But provided you have drivers properly installed for both, then you should test with the software you intend to use.

14 hours ago, bakayarooo said:

I will be using Linux for the ML. With Linux you can use Nvidia's NCCL drivers to direct your work load to a specific GPU even though it is not connected to a

monitor.

That tells me you shouldn't find the same problems in Linux since you won't be tied to Nvidia's drivers (assuming you don't find windows drivers compatible with both in their website). But you can just make a live boot USB and test it.

[sdmn666]

On 2/15/2020 at 5:58 AM, bakayarooo said:

I think I read that with Windows you can not use two cards that are not on the same DirectX. I tried to add a GTX 1080Ti and an RTX Titan in the same machine. I opened Blender and only the Titan showed up. I originally had the Titan installed and wanted to add the 1080Ti. Does Linux have the same limitation as Windows where both cards have to run the same DirectX? Has anyone tried to do this?

well, It woked for me fine. I used an RTX 2060 & GTX 1070Ti. I ran blender 2.93 and used cycles engine. Both GPU worked fine. For some reason it didnt work for blender 3.0. Make sure the drivers are installed properly. I setted up RTX 2060 first then installed the 2nd one. Both using the same directX version. 
I even tried on cinema4D redshift and it woked fine too.