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Old 07-06-10, 10:15 AM   #1
cbstryker
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Default Multi-GPU, wrong GPU is used to render, how to change?

So I've been having a bit of an issue with Lord of the Rings Online performance recently. I've played LOTRO in the past in CXGames (Crossover Games) for years and never had a problem, LOTRO always ran like a champ, even better than in Windows in some cases.

However, a little while ago I got a second video card to use as a simple VGA passthrough for a third monitor, and of course I want to do triplehead gaming. But I've been noticing, even with the game on only 1 monitor it's very laggy (when across more than 1 screen with settings set to lowest it's still laggy, but with just one screen it seems ok), almost as if it's using the slower card. So here is my system:

Ubuntu 10.04 64bit
Asus P5K Motherboard
Q6600 overclocked to 3.07GHz (stable)
8GB DDR2 overclocked to 1000Mhz (stable)
3 Monitors, each a separate X screen with Xinerama enabled.
GeForce 260 GT running screen 0 (main screen) and 1
GeForce 8400 GS running screen 2

Screens arranged as 2,0,1

When I type "glxheads" and "glxheads :0" both give me this:

Code:
chris@chris-ubuntu:~$ glxheads :0
Name: :0.0
  Display:     0x68f6d0
  Window:      0x5200002
  Context:     0x6ba368
  GL_VERSION:  3.3.0 NVIDIA 256.35
  GL_VENDOR:   NVIDIA Corporation
  GL_RENDERER: GeForce 8400 GS/PCI/SSE2

So I think what's been happening is that everything has been using the 8400GS and not the 260GT this whole time, but how can I confirm this and how can I change it?

BTW, I've tried adding " :0" to the launcher for LOTRO with no effect, but then again glxheads had no impact with that either.

Also, when I disable the one screen on the second GPU, "glxheads" shows "GeForece 260 GT" in the output and the spinning graphic is almost a blur compared to doing it with the "GeForce 8400 GS". So this clearly is an issue of the wrong GPU being used.

I've also checked "glxinfo". Notice towards the bottom it says "GeForce 8400 GS" and nowhere does it mention my GeForce 260 GTX.

The output of glxinfo:

Code:
chris@chris-ubuntu:~$ glxinfo
name of display: :0.0
display: :0  screen: 0
direct rendering: Yes
server glx vendor string: NVIDIA Corporation
server glx version string: 1.4
server glx extensions:
    GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_SGIX_fbconfig, 
    GLX_SGIX_pbuffer, GLX_SGI_video_sync, GLX_SGI_swap_control, 
    GLX_EXT_swap_control, GLX_EXT_texture_from_pixmap, GLX_ARB_create_context, 
    GLX_ARB_create_context_profile, GLX_ARB_multisample, GLX_NV_float_buffer, 
    GLX_ARB_fbconfig_float, GLX_EXT_framebuffer_sRGB
client glx vendor string: NVIDIA Corporation
client glx version string: 1.4
client glx extensions:
    GLX_ARB_get_proc_address, GLX_ARB_multisample, GLX_EXT_visual_info, 
    GLX_EXT_visual_rating, GLX_EXT_import_context, GLX_SGI_video_sync, 
    GLX_NV_swap_group, GLX_NV_video_out, GLX_SGIX_fbconfig, GLX_SGIX_pbuffer, 
    GLX_SGI_swap_control, GLX_EXT_swap_control, GLX_ARB_create_context, 
    GLX_ARB_create_context_profile, GLX_NV_float_buffer, 
    GLX_ARB_fbconfig_float, GLX_EXT_fbconfig_packed_float, 
    GLX_EXT_texture_from_pixmap, GLX_EXT_framebuffer_sRGB, 
    GLX_NV_present_video, GLX_NV_copy_image, GLX_NV_multisample_coverage, 
    GLX_NV_video_capture
GLX version: 1.4
GLX extensions:
    GLX_EXT_visual_info, GLX_EXT_visual_rating, GLX_SGIX_fbconfig, 
    GLX_SGIX_pbuffer, GLX_SGI_video_sync, GLX_SGI_swap_control, 
    GLX_EXT_swap_control, GLX_EXT_texture_from_pixmap, GLX_ARB_create_context, 
    GLX_ARB_create_context_profile, GLX_ARB_multisample, GLX_NV_float_buffer, 
    GLX_ARB_fbconfig_float, GLX_EXT_framebuffer_sRGB, 
    GLX_ARB_get_proc_address
OpenGL vendor string: NVIDIA Corporation
OpenGL renderer string: GeForce 8400 GS/PCI/SSE2
OpenGL version string: 3.3.0 NVIDIA 256.35
OpenGL shading language version string: 3.30 NVIDIA via Cg compiler
Any ideas?

Also sorry if my post is a mess, I've combined a couple of my posts from Ubuntu forums to make this one. Since no one there has been helping out with this.
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Old 07-15-10, 05:43 PM   #2
cbstryker
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Default Re: How to tell which GPU is used to render?

Still no replies?
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Old 07-16-10, 12:19 PM   #3
Stephen Warren
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Default Re: How to tell which GPU is used to render?

If you have physically separate X screens without Xinerama, they're named ":0.0", ":0.1", and ":0.2". Perhaps try experimenting with those DISPLAY values? But, if it's displaying on the screen physically connected to the faster GPU, it's extremely likely it's rendering there. Xinerama might complicate things; I forget exactly how that works in OpenGL.
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Old 07-18-10, 11:33 PM   #4
cbstryker
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Default Re: How to tell which GPU is used to render?

Quote:
Originally Posted by Stephen Warren View Post
If you have physically separate X screens without Xinerama, they're named ":0.0", ":0.1", and ":0.2". Perhaps try experimenting with those DISPLAY values? But, if it's displaying on the screen physically connected to the faster GPU, it's extremely likely it's rendering there. Xinerama might complicate things; I forget exactly how that works in OpenGL.
Thanks for the reply,

So with Xinerama running, I have the game extended halfway on to the left and right monitors. So instead of having the full 4240x990 resolution I have it at 3000x990. You don't think it's not using the faster video card then?
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