Monitor Refresh Rate

[Big P]

Hi,

I own a 21" CRT monitor, a Dell Trinitron, and I was using nvidia-settings to set the refresh rate (hz) and resolution. Afaik, my monitor was running at 1600x1200@75hz as I thought until today when I tested out xrandr.

It gives the following (relevant) output:

 SZ:    Pixels          Physical       Refresh
*0   1600 x 1200   ( 383mm x 290mm )  *50   51   57   58   59  
 1   1280 x 1024   ( 306mm x 247mm )   52   63   64  
 2   1152 x 864    ( 276mm x 209mm )   53  
 3   1024 x 768    ( 245mm x 185mm )   54   68   69   70   71   72  
 4    800 x 600    ( 191mm x 145mm )   55   78   79   80   81   82   83   84   85   86   87

As you can see, X is actually running at 50hz, and the available refresh rates are unusual. In windows this same monitor runs at 1600x1200@85hz (at least according to nvidia drivers).

The nvidia drivers in both windows and linux see the monitor as "DELL D1626H", and the following are the relevant sections of my xorg.conf (which i got from nvidia-settings "Save to X configuration file" option.

Section "Monitor"
    # HorizSync source: edid, VertRefresh source: edid
    Identifier     "Monitor0"
    VendorName     "Unknown"
    ModelName      "DELL D1626HT"
    HorizSync       30.0 - 107.0
    VertRefresh     50.0 - 160.0
    Option         "DPMS"
EndSection

Section "Device"
        Identifier  "Card0"
        Driver         "nvidia"
        VendorName     "NVIDIA Corporation"
        BoardName      "GeForce 6600 GT"

        Option "CursorShadow"  "on" 
        Option "RenderAccel" "true"
        Option "XAANoOffscreenPixmaps" "true"
EndSection

Section "Screen"
        Identifier "Screen0"
        Device     "Card0"
        Monitor    "Monitor0"
        DefaultDepth 24
        Option "AddARGBGLXVisuals" "True"
        Option "DisableGLXRootClipping" "True"

    Option         "metamodes" "1600x1200_75 +0+0; 1600x1200 +0+0; 1280x1024_75 
+0+0; 1152x864 +0+0; 1024x768 +0+0; 800x600 +0+0; 640x480 +0+0"
    SubSection     "Display"
        Depth       24
        Modes      "1600x1200" "1280x1024" "1024x768" "800x600" "640x480"
    EndSubSection
EndSection

Any help on getting my refresh rate fixed would be greatly appreciated. If I can give any more info please let me know.

Regards,

[netllama]

This is expected behavior. See the driver README's discussion (or any of the past discussions on this forum) of DynamicTwinview.

Thanks,
Lonni

[Big P]

Ah, thank you for the very fast reply. I understand now.

As a follow up question, would the refresh rate of my monitor be tied into the fps I obtain in games? I have ut2004 which for some reason is capped at 50fps when I play online and it feels very jerky, whereas in windows it doesn't (and is capped at 85fps). I was hoping the reason its capped at 50 was to do with my monitor being capped at 50hz, but as I can see that isn't true.

I'm a little confused, because other people I know run it at 85fps in linux also and some I've heard are capped at 62 fps.

Regards,

[netllama]

The only reason why any application would have a fixed FPS equal to your refresh rate is if you've set __GL_SYNC_TO_VBLANK=1 somewhere in your environment.

How did you determine that your game is maxing out at 50FPS?

[Big P]

Hi thanks again for the reply. I can determine that my fps are limited by doing "stat fps" in the console while playing ut2004 online. Offline I get about 200fps, however online it is limited to 50 (for me). I have read that the fps cap is tied down to your netspeed, however in windows I get 85fps with the same config. Perhaps the issue at hand is ut2004 and not related to the nvidia drivers, but I don't understand how other linux users with ut2004 and nvidia cards have 62fps or 85fps or whatever other limit.

ps. Sync to vblank is disabled in my nvidia-settings anyway, so I doubt its the cause (its not in my UT2004.ini or User.ini).

[netllama]

Its possible that the game is querying the refresh rate of the display from xrandr, which would be erroneous. What you could try doing is setting DynamicTwinview to false in xorg.conf, and see if that makes a difference in the game. If so, then this is arguably a game bug.