Ubuntu – Extremely low 3D perfomance


I recently bought a Radeon HD 6850 and installed a fresh version of 12.04 on my computer.

It has 4GB RAM, a somewhat fast CPU and a suprisingly fast S-ATA HDD.

However I noticed that my 3D performance is extremely low, which causes the whole system to be slow.

As mentioned in this question, glgears has an average FPS of 70 and fgl_glxgears an average of 45.

I am using Unity 2D and have the supported driver from "Additional Drivers" installed. (not the post-release one).

fglrxinfo Output:

display: :0  screen: 0
OpenGL vendor string: Advanced Micro Devices, Inc.
OpenGL renderer string: AMD Radeon HD 6800 Series 
OpenGL version string: 4.2.11627 Compatibility Profile Context

glxinfo | grep rendering: direct rendering: Yes

xvinfo Output

I noticed this problem already when installing, so I tried the current release from AMD's website and an older one (11.X) – both didn't work as intended, as they had some weird glitches sometimes.

After that I reinstalled Ubuntu, so there is nothing from that that could interfere.

Does anyone of you have an idea what is going on?

/edit: unity_support_test Output:

OpenGL vendor string:   ATI Technologies Inc.
OpenGL renderer string: AMD Radeon HD 6800 Series 
OpenGL version string:  4.2.11627 Compatibility Profile Context

Not software rendered:    yes
Not blacklisted:          yes
GLX fbconfig:             yes
GLX texture from pixmap:  yes
GL npot or rect textures: yes
GL vertex program:        yes
GL fragment program:      yes
GL vertex buffer object:  yes
GL framebuffer object:    yes
GL version is 1.4+:       yes

Unity 3D supported:       yes

Best Answer

  • The first thing I would do is install the newer versions of FGLRX, as you have the version available at distro release. you do not need to get a version from AMD, at this point, you can get the updates version from the repository.

    First uninstall your current version.

    sudo apt-get purge fglrx fglrx-amdcccle

    Then install the newest version, available in the repository

    sudo apt-get install fglrx-updates fglrx-amdcccle-updates

    Restart your computer, Log back in your desktop, report your FPS results again.

    I also want to mention, You will get very low framerates if you have "Wait for vertical refresh" set to any of the "ON" options. Make sure it is set to "Off, unless application specifies" You can find it in the Catalyst Control Center. That is the only other reason, which I could think of, that would cause such low FPS on a correct configuration. I'm 100% serious, you need to check on this setting. This is not a mere suggestion, it is that significant to the FPS scores.