# External monitor and refresh rate

**URL:** <https://psychtoolbox.discourse.group/t/external-monitor-and-refresh-rate/3907>\
**Category:** Hardware\
**Tags:** linux\
**Created:** [June 23, 2021, 9:24pm UTC](https://psychtoolbox.discourse.group/t/external-monitor-and-refresh-rate/3907 "2021-06-23T21:24:52Z")\
**Posts on this page:** 1\
**Showing post:** 2

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**Author:** ![mariokleiner](https://avatars.discourse-cdn.com/v4/letter/m/13edae/32.png) [@mariokleiner](https://psychtoolbox.discourse.group/u/mariokleiner)\
**Post date:** [June 24, 2021, 12:53pm UTC](https://psychtoolbox.discourse.group/t/external-monitor-and-refresh-rate/3907/2 "2021-06-24T12:53:42Z")

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> [@alexchalard](#):
>
> Hi team,
> 
> I want to run my experiment with a laptop (linux) and display the experiment only on an external screen.  
> I used the XorConfCreator, when I try to select this configuration with XorgConfSelector I end up with the following error :  
> cp ; cannot create regular file ‘etc/X11/xorg.conf.d/90-ptbxorg.conf’ : No such file  
> Any idea how to go through ?

Did you install from NeuroDebian or your Ubuntu/Debian distribution, instead of via `DownloadPsychtoolbox` or `SetupPsychtoolbox`? Then you should run `PsychLinuxConfiguration` manually once. It runs automatically as part of [Download-/Update-/Setup-]Psychtoolbox, but needs manual invocation when installing from NeuroDebian. That script will create the /etc/X11/xorg.conf.d/ directory and set suitable permissions, so `XOrgConfSelector` can do its job.

> [@](#):
>
> I am designing an experiment that will record the mouse coordinates, if I correctly understand the frequency rate of the mouse acquisition is given by the refresh rate of the screen (in that case 60Hz).  
> If I want to increase this number, and I purchase a monitor with 144 or 240Hz refresh rate, will I be able to record the mouse at this frequency rate ?

That understanding is wrong, at least on current Linux + X11 X-Server, as used by Psychtoolbox. I think macOS has that limitation, so if you are coming from there, that’s why you’d think that.

The mouse is polled and reported at most as fast as it asks to be polled. Typical desktop mice request 8 msecs / 125 Hz polling. Some gaming mice can ask for up to 1 msec / 1000 Hz.

The monitor doesn’t matter for that on Linux + X11.

We have a test function `HIDIntervalTest` to allow to check the polling rate. Also `MouseMotionRecordingDemo` to show optimal mouse movement recording on Linux, and with more limited reliability on Windows, but not on macOS.

Please buy a (`help PsychPaidSupportAndServices`) community membership with priority support to support PTB ongoing maintenance, development and support. Any further advice or comments from my side will require that anyway.

Best,  
-mario

> [@](#):
>
> To use these kind of monitor do the laptop need a GPU ? or if it is running with a basic Intel HD Graphics 520 (Skylake 2) I will be able to use these refresh rate ?
> 
> Thank you
> 
> All the best,
> 
> Alex

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