Showing results for 
Search instead for 
Did you mean: 

Archives Discussions

Catalyst/AMD APP not detecting second discrete GPU.

Hello everyone,

I have the following sytem configuration right now:

Motherboard: ASUS P8P67

PCIE x16(BLUE)  : ASUS Radeon HD 7970

PCIE  x4(BLACK) : Sapphire Radeon HD 4890

OS: Ubuntu 12.04(x64), Catalyst ver:12.4 ,   AMD APP 2.6

OS: Windows 7(x64)   , Catalyst ver 12.10,  AMD APP 2.5

Both the OS detect  the second card in hardware information but catalyst/APP doesn't detect the second GPU in either OS. 

In ubuntu I checked using lspci command.

In windows I checked using hardware information GUI.

When my monitor is attached to the 7970 and I get output on the screen. However when I connect the monitor to 4890 while the 7970 is still in the x16 slot I don't get any output on screen.

How do I use my 4890 for opencl only and the 7970 for both opencl and display ?

It would be greatly helpful if anyone can provide a step by step tutorial for both OSes. 



4 Replies

Under linux you need to make sure that there is a device section for each gpu in your /etc/xorg.conf. An easy way to achieve is with the aticonfig utility:

aticonfig --initial -f --adapter=all

should do the trick.

You can check which devices are being detected by the opencl runtime by running the clinfo tool.

Note that the 4890 is fairly old and does not fully support OpenCL. I'm not sure what functionality is missing (I believe it has limited support for __local memory). Also in terms of performance it may not be worth using it in addition to the 7970.

Did that.

Now the catalyst has control over both the GPUs.

sayantan@Eden:/usr/bin$ aticonfig --adapter=1 --odgc

Adapter 1 - ATI Radeon HD 4800 Series          

                                Core (MHz)    Memory (MHz)

          Current Clocks :    240           975

             Current Peak :    850           975

  Configurable Peak Range : [500-1000]     [975-1200]

                 GPU load :    0%

sayantan@Eden:/usr/bin$ aticonfig --adapter=0 --odgc

Adapter 0 - AMD Radeon HD 7900 Series

                            Core (MHz)    Memory (MHz)

           Current Clocks :    300           150

             Current Peak :    925           1375

  Configurable Peak Range : [300-1125]     [150-1575]

                 GPU load :    0%

However clinfo does not show the two GPUs. It only detects Tahiti. I did a reinstall(installed again without un-installing first) of APP 2.6 but the probelem persist.

Any suggestions?


Why dont you instal APP SDK 2.7 and Catalyst 12.10 on "both" OSes?


First of all AMD has official support for both the devices together in catalyst 12.4. After that AMD has separate drivers for 7970 and 4890.

Similarly APP SDK 2.6 has support for both devices. APP SDK 2.7 requires catalyst 12.5 or above , so it is not an option.