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Old 07-28-2004, 05:51 PM   #1
ianunderwood
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Refresh rates and colour depth


Two questions related to monitor settings. I tend to use the SaX2 tool under SuSE, but I can obviously edit XF86Config if necessary.

o Firstly, why is the highest colour depth that I can select 24 rather than 32 bit? (I don't know if it's relevant but I'm using the latest nvidia drivers, and my card is a Gainward FX5900/1100XT Golden Sample.)

> o Secondly, why does it only ask for a _range_ of horizontal and vertical frequencies? (How does it work
> out the highest frequency it can use for a given resolution from those values?)
>
> I use 1024*768 (because my monitor can only do 60Hz at 1280*1024), and I want to make sure it uses the
> highest possible refresh rate for my monitor at that res, 85Hz. How do I go about this?

EDIT: Just found how you choose a frequency setting in KDE under Control Center/Peripherals/Display. Sorry! Should have looked harder. First question still stands, I think.

Thanks

Ian

Last edited by ianunderwood; 07-28-2004 at 05:57 PM.
 
Old 07-28-2004, 09:35 PM   #2
jailbait
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"o Firstly, why is the highest colour depth that I can select 24 rather than 32 bit? (I don't know if it's relevant but I'm using the latest nvidia drivers, and my card is a Gainward FX5900/1100XT Golden Sample.)"

The answer is related to how much video memory you have. The color depth means how many bits are used to describe each pixel's color. You also set the number of pixels with the resolution, in this case 1024 x 768 = 786432 pixels. So you have enough video memory to display 786432 pixels at 24 bits per pixel but not enough memory for 32 bits per pixel. You can configure your monitor to display more colors at a lower resolution or fewer colors at a higher resolution. If you want more colors at the same or higher resolution you need more video memory.

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Old 07-29-2004, 02:53 AM   #3
ianunderwood
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But I _can_ (and do) display at 32 bit in windows at any resolution that my monitor supports (including 1024*768, but right up to 1280*1024). Besides, I have 128MB of video RAM, so I doubt it can be lack of memory. All games I run under Linux (Neverwinter Nights, Unreal Tournament 2004, Quake III, various games under WineX) will happily go into 32 bit mode.

Cheers

Ian

EDIT: I've just had another go under SaX2. It doesn't matter how low I set my resolution; the list of available colour depths only goes up to 24 bit.

As a side point, if you multiply 786432 by 32, divide it by 8 (to get bytes), then by 1024 to get KB, and finally 1024 again to get MB, you get 3 -- i.e. 3MB! So I have over 40 times the required memory, I think.

Last edited by ianunderwood; 07-29-2004 at 03:10 AM.
 
Old 07-29-2004, 10:13 AM   #4
jailbait
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"I have 128MB of video RAM, so I doubt it can be lack of memory."

You are right. Video memory is probably not your problem. You might be able to fix the problem by using sax2 in expert mode. Go to monitor and click on properties and then 'expert' tab to enter your monitor specifications by hand. You will need to know your screen height and width in millimeters to use the expert mode. Try entering 32 bit in expert mode.

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Old 07-29-2004, 10:53 AM   #5
ianunderwood
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This thread is worth a look. Seems 24 bit is as high as you can go with X.

Ian
 
Old 07-29-2004, 11:45 AM   #6
qwijibow
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ugh....

24 bit is the same as 32bit !

8bits RED + 8Bits Green + 8Bits Blue + 8bits Alph

Alpha is only used for Blending 3d OpenGL Games and is irrelevant on the Desktop.

so even if you set C to use 32bits, you will not get any more colours !

as soon as you fire up Unreal tournament in 32bit colour mode, your display will switch to 32 bit colour.. untill then, when you are on the desktop, there's no point.

MS just calls it 32bit, because well.. i dont know.. maybe because the Games are not seperate from the desktop GUI, or maybe cos it just sounds better.

Last edited by qwijibow; 07-29-2004 at 11:47 AM.
 
  


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