[Sderby] UK Ubuntu Team

[Tim Retout]

On Sun, 2006-11-12 at 13:04 +0000, R Verma wrote:
> After trying several downloaded versions of Linux, none of which I managed
> to install on my stand alone machine satisfactorily, I eventually got a
> complete copy of Ubuntu as a freebee with one of the computer magazines. I
> have for the first time ever managed to install it successfully. My problem
> is that I am using a 20 inch Iiyama Vision Master Pro 510 monitor and I get
> a lot of flicker. With my XP I get a rock solid image with no flicker. How
> do I improve the image on my screen when using Ubantu? In Windows I can
> change the refresh rate etc. but the flicker in Ubantu is so annoying that I
> have not played with it at all.

Right, I remember this from 14th August. You have an NVidia GeForce FX
5200.

There are a couple of things that might be going wrong:


* If you are seeing flicker only when moving windows about, or when
using graphics-intensive applications, you may be using the default 'nv'
driver for your graphics card, which does not have 3D hardware
acceleration.

In other words, most of your graphics card is not being used, and your
computer's main processor has to do all the work - it is struggling to
keep up, so you see flicker. Here are some instructions for changing to
the binary-only NVidia drivers, which do not come with source code, but
may make your graphics card run better:

http://doc.gwos.org/index.php/Latest_Nvidia_Dapper

(The FSF would not approve.) :(


* If it is the whole screen flickering all the time, then this is a
different problem. (That's not to say that changing the driver won't
improve performance, but it might not be the real problem.)

The refresh rate of the monitor might be set incorrectly. Here is a case
of someone with an Iiyama monitor experiencing a similar problem:

http://ubuntuforums.org/archive/index.php/t-2072.html

Here is a slightly technical guide to configuring your X server:

http://ubuntuforums.org/showthread.php?t=83973

You want the bit under the heading 'How to edit or add HorizSync and
VertRefresh lines'. From a quick search via Google, these are the
correct settings for your monitor:

HorizSync   30-130
VertRefresh 50-160

The 'Identifier' setting should already be there, and should match the
'Monitor' line in the 'Screen' section.


* It could be something else altogether, which I've not thought of.


Do write back if any of this helped/didn't help. :) Incidentally, the
Ubuntu forums are said to be quite friendly to beginners, and seem to be
useful sources of information.

Please don't be put off if I or anyone else fails to estimate your level
of technical ability correctly - that's the last thing anyone wants, I
think.

-- 
Tim Retout <tim at retout.co.uk>

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