# Monitor Refresh Rates [noob]

## MrSplinter

New @ Gentoo and experiencing annoying troubles with my monitor.

It's a AOCA770 (HorizSync 30-70kHz and VerticRefresh 50-130Hz).

I've corrected these values in xorg.conf but I always keep a screen which is high-frequently "shaking"

It looks like everything trembles from left to right but only the vertical borders of any window are unstable   :Confused: 

I'm not sure if it's important: my video card is a Medion ATI X740XL

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## simon_irl

most monitors have a function to display the refresh rate they're currently using (mine displays it at the top of the configuration menu as soon as i press the settings button). does yours? if so, what (vertical) refresh rate does it report?

on my system, X automatically uses the highest possible refresh rate based on the monitor info (the refresh ranges you posted) and the graphics card driver, but maybe yours needs modelines. if you find (from the monitor) that, for example, you're viewing 1280x1024 at only 60Hz when your graphics card and monitor can both in fact draw it at 85Hz (or whatever), use something like the xfree86 modeline generator to calculate a modeline for 85Hz and then put that into your xorg.conf (google for examples of how you can do this). if your problem is indeed a low refresh rate, this ought to fix it...although the way you describe it shaking about, i'm thinking it might be something else. anyway, the refresh rate reported by the monitor ought to give you a better idea what's going on.

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## yabbadabbadont

It sounds more like a problem I used to have.  My monitor claims to be able to handle 85Hz refresh rate, but text would "swim" at that setting.  (it would slowly shift back and forth from right to left in a band that would move down the screen) I had to lie to X in my xorg.conf to get it to use a lower value.  (75Hz)

Here is what I did:

```
VertRefresh     50.0 - 80.0
```

If I used any value higher than 80, it would insist on using 85Hz.

I hope it helps.

P.S.  Woo Hoo!  1000 posts.

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## simon_irl

ah, that sounds more like your description of what's happening...and it's a much quicker and easier solution to test...so don't even bother with modelines until you've tried yabbadabbadont's fix!

what i was coming back to say was, if you ever *do* need a modeline, the "sax2" utility that ships with suse linux is the best tool i've ever seen for generating them...it was the only tool that managed to produce a decent 120Hz 720x576 display that X would accept.

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## MrSplinter

Thx for helping so much guys!!  :Embarassed: 

First of all, my monitor settings at this moment: 60.0kHz and 75.0Hz/75.1Hz

Actually yabbadabbadont describes the best how text is "swimming".

So I changed my values to 50-80/50-75/50-70 but without result  :Sad: 

I'll play a little more with those settings, otherwise I'll try simon_irl's solution.

EDIT I often get 68.5kHz and 84.9Hz as monitor settings too!

Tried a few more frequencies in xorg and at 85Hz the "waves" slow down, stand still and start again.

It must be close to 85 I suppose...

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## MrSplinter

Tried the modeline calculator.

I inserted these values:

resolution: 1024x768

refresh rate: nothing (after calculation "Actually 85.49" appears)

dot clock freq: nothing (after calculation "101.55 MHz appears)

constrain aspect ratio: 4/3

interlace and doublescan disabled

Answer:

Modeline "1024x768@85" 101.55 1024 1056 1440 1472 768 782 793 807

Horizontal sync frequency: 68.98 kHz

 :Question:  How can I adapt my xorg.conf correctly, because I added Modeline..., changed the HorizSync value and put # before VertRefresh but, when pressing Alt+Ctrl+BS my login is incorrect  :Rolling Eyes: 

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## simon_irl

sorry things still aren't working for you. this is an excerpt from my xorg.conf, so you can see how a modes section can be linked to a monitor section:

```

Section "Monitor"

    Identifier  "AOC"

    DisplaySize 360 270

    HorizSync   30-95

    VertRefresh 50-160

    UseModes "Modes0"

EndSection

Section "Modes"

    Identifier "Modes0"

    Modeline "1280x1024" 163.41 1280 1360 1496 1744 1024 1025 1028 1077

    Modeline "1024x768" 130.12 1024 1096 1208 1392 768 769 772 820

    Modeline "800x600" 90.10 800 856 944 1088 600 601 604 647

    Modeline "720x576" 77.58 720 768 848 976 576 577 580 621

    Modeline "640x480" 57.18 640 680 752 864 480 481 484 517

EndSection
```

but i'm not sure if modelines are going to help you...i've never seen the behaviour you and yabbadabbadon't are describing. still, if you've run out of other options, it can't hurt to try. it might pay to try with a lower refresh rate, too (even as low as 72Hz can be bearable). good luck!

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## cylgalad

HorizSync & VertRefresh are most of the time not needed : try without them, it should work. They are needed only for non-pnp screens (like TV and very old monitors).

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## agent_jdh

```
gtf 1024 768 85
```

Spits out the correct modeline for 1024x768 @ 85Hz.  Modify it for what you want.  It'll give you a modeline that starts "1024x768_85.00 - just remove the _85.00 part when you c&p it into xorg.conf.

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## MrSplinter

I've tried a lot more possibilities for max VertRefresh without result

although I've to repeat that at 85Hz the "waves" almost stand still.

Here's a view of my xorg:

```
Section "Monitor"

    Identifier  "ADC"

    HorizSync 30-70

    VertRefresh 50-76

    Option "DPMS"

    UseModes "Modes0"

EndSection

Section "Modes"

   Identifier "Modes0"

   Modeline "1024x768" 101.55 1024 1056 1440 1472 768 782 793 807

   Modeline "800x600" 58.99 800 832 1056 1088 600 611 620 631

   Modeline "640x480" 36.72 640 672 808 840 480 489 496 505

EndSection
```

I also tried to delete HorizSync and VertRefresh but that didn't help neither.

I read about this Video timing calculator, worth another try  :Razz: 

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## yabbadabbadont

You said that your video card is an ATI.  Do you know if the driver has an option to tell it to ignore the EDID information from the monitor?  I use nvidia and have to add an option UseEdidFreqs and set it to false in order to get the newer nvidia drivers to accept the frequency settings I specified.  Perhaps the ATI drivers do something similar?

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## MrSplinter

I'm not sure where to find this information.

But while searching I found this:

```
Section "Device"

# === Screen Management ===

# Note: When OpenGL Overlay is enabled, Video Overlay

# will be disabled automatically

# no device found at config time

Identifier "ATI Graphics Adapter"

Driver "fglrx"

Option "no_accel" "no"

Option "no_dri" "no"

# === misc DRI settings ===

Option "mtrr" "off" # disable DRI mtrr mapper, driver has its own code for mtrr

Option "DesktopSetup" "0x00000000"

Option "MonitorLayout" "LVDS, CRT"

Option "IgnoreEDID" "off"

# Option "HSync2" "65"

# Option "VRefresh2" "60"

# Option "Mode2" "1280x720"

# Option "ScreenOverlap" "1" 
```

Mine is:

```
# === ATI device section ===

Section "Device"

    Identifier                          "ATI Graphics Adapter"

    Driver                              "fglrx"

# ### generic DRI settings ###

# === disable PnP Monitor  ===

    #Option                              "NoDDC"

# === disable/enable XAA/DRI ===

    Option "no_accel"                   "no"

    Option "no_dri"                     "no"

# === misc DRI settings ===

    Option "mtrr"                       "off" # disable DRI mtrr mapper, driver has its own code for mtrr

# ### FireGL DDX driver module specific settings ###

# === Screen Management ===

    Option "DesktopSetup"               "0x00000100"

    Option "MonitorLayout"              "AUTO, AUTO"

    Option "IgnoreEDID"                 "off"

    Option "HSync2"                     "31.5 - 48.4"

    Option "VRefresh2"                  "50 - 70"

    Option "ScreenOverlap"              "0"
```

I'll try to make it  

```
Option "IgnoreEDID" "on"
```

and put VRefresh2 and HSync2 between brackets

Should I change something to this? 

```
# === disable PnP Monitor  ===

    #Option                              "NoDDC"
```

EDIT:  tried those 3 possibilities -->   :Crying or Very sad:   :Mad: 

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## MrSplinter

I eventually bought a Samsung SyncMaster 710 17" TFT monitor and everything works now   :Confused: 

This topic is not really worth a SOLVED tag   :Laughing: 

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