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Helmut

frame rate in mdk slower

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I have two PC's and each has a different 17 inch monitor. With mdk2007 and 1024 x 768 they both run at around 75 or 85Hz, but under Windblows they will run at 100Hz. Because of this, vertical and horizontal size of the picture varies according to which OS was booted. Both have graphic cards from Nvidia, different models about two or three years old. There is no difference in speed with or without 3D drivers.

 

Question: Is there a way to get them running at full 100Hz in Mandriva?

 

Cheers,

Helmut

Edited by Helmut

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The monitor has to be correctly identified when you were configuring your video card. If it's just set as a generic one, then you won't get the features that your monitor supports. Chance are you have a generic or incorrect monitor selected, which is why you can only got so high on the Hz levels.

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If your monitors are CRT:-

You do NOT gain anything by wanting to run all of your crt Monitors at maximum refresh rate such as 100. I repeat NONE.

 

Your eye CANNOT see any difference in refresh rates above 60/63 cycles.

There is no earthly reason that you cannot run all your monitors at 70 or at 75 in both Windows and Linux. That way your screen size presentation remains constant to all machines and all screens and all OSs.

Anything else is just like the nonsense of wanting to shorten the bootup time by 2 or 3 seconds, namely it is irrational and of no practical importance or value.

 

If your monitors are LCD:-

I too used to be concerned that my lcd monitor had only 60 cycles (currently running 55) until iphitus reminded (correctly. I should have remembered being a former RAAF trained Radio and Radar Tech and former Medical Electronics Engineer) me that unlike Crt screens the lcd screen is not refreshed as in crt technology. There is NO flicker on my lcd screen at 55 but on my 21" crt at 55cycles it would have been almost unviewable for any length of time.

 

Just set all CRTs to 70 or 75 in both OSs and you will never notice a difference or have any flickering.

Just set all your LCDs to 60 or 55.

 

Cheers. John.

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Thanks for the replies!

Both monitors are CRT's, and both are identified 100% correctly in Linux. At the chosen resolution (1024x768), they could both run at 160Hz, but actually run at less than half under Linux. Under Windows, they run at 100Hz, probably limited by the graphics card.

 

This is what causes a problem: When you change their frame rate, such as between 75 and 85 or 100 Hz, horizontal and vertical size and position becomes different. On a dual-boot machine, you therefore need to fiddle with monitor adjustments every time you boot up to a different OS.

 

John, I know you can't see any difference between, say 72Hz and 100Hz, but it is less distressing on your eyes. Very slow rates such as 60Hz is definitely bloody aweful to eyes, and you can tell the flicker. (I say that as someone who earns a living retouching old films on computer CRT-screens. Those sort of screens at work are 21-inch screens, the tools being on one screen, and the image under construction on the other, with my eyes at about 45-50cm distance.)

 

I was wondering, why is the frame rate slower with Nvidia cards running under Linux, even with Nvidia drivers? Is there a way to change that?

Cheers and happy hollidays,

Helmut

Edited by Helmut

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manually editing your /etc/X11/xorg.conf might be able to correct this. Look for the monitor section, it holds the vertical refresh and horizontal sync ranges. if you input the proper numbers you should be able to get higher refresh rates.

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The xorg.conf reads:

 

Section "Monitor"

Identifier "monitor1"

VendorName "Eizo"

ModelName "Eizo T57S"

HorizSync 30.0-92.0

VertRefresh 50.0-160.0

 

# TV fullscreen mode or DVD fullscreen output.

# 768x576 @ 79 Hz, 50 kHz hsync

ModeLine "768x576" 50.00 768 832 846 1000 576 590 595 630

 

# 768x576 @ 100 Hz, 61.6 kHz hsync

ModeLine "768x576" 63.07 768 800 960 1024 576 578 590 616

EndSection

 

The other monitor is a Samsung Syncmaster 700S, essentially with very simlar technical data.

 

Cheers,

Helmut

Edited by Helmut

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Hello helmut. I still think you do not have a problem.

I too am a professional photographer (25 yrs) so I can appreciate the concentration that you use when doing restoraton work on screen.

That concentration causes the eye weariness and NOT the fact that the monitor might be using 75 as against 100. A large measure of eye wearness can be caused by brightness and contrast settings being higher than usual (often done to show up detail error better in old images when doing restoration). On 21" screen (yes I have one) this eye soreness can be bad enough but with 17" screens this has to be watched more carefully since you are concentrating on smaller visual detail.

 

Cheers. John

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Hello John,

I understand you point. Maybe I will just enter the same slower frame rate for windows too, as you suggested further up That way both Linux and Windows will be displaying at the same frame rate, and hence the monitors will need no fiddling with. Thankfully I don't need Windows very often, maybe once a month or so.

 

I do think a Nvidia card in Linux should be able to run at the same (higher) frame rate as with the same setup under XP. The Monitor is recognized correctly and the card is so too. Both can put out much higher frame rates, so it makes me wonder what is limiting them. Maybe this is a general problem of the Linux Nvidia driver, and might illuminate work needing to be done.

Cheers,

Helmut.

Edited by Helmut

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