nvidia 8800GT & 60hz refresh rate problem...

[penestijeras]

Hi all,

 

I have an almost perfect hackintosh Kalyway 10.5.2 running very well except the refresh rate. My LCD (LG L194WT 19") is detected as 1440x900x32@60hz, but at WindowsXP it is detected as 75hz. My graphic card is Nvidia 8800 GT 512 Mb (latest nvinject)

 

My question is if there any way to force re detecting correctly the 75hz refresh rate. I also know that it could works if I edit com.apple.boot.plist, but I would like to know if it exist a native method (I bought the hardware trying to get the most compatible...)

 

What do you recommend me? Thank you a lot in avance!

[sg]

why do you want a different refresh rate while on a LCD? there technically is no refresh rate on LCDs. just use whatever is detected.

[zeba]

Please I'm also interested!

I have a 19" Viewsonic VX912 LCD and before when I used windows I noticed flickering in the picture while on 75Hz, so I went with 60Hz.

Now with OsX I have chosen 60Hz, but still get flickering.. and it's still there after changing to 75Hz.. Is it possible that it runs on 75Hz all the time?

I have a 8600GT.

 

Thanks! Hope this will be solved, the flickering is quite annoying

[verdant]

Please I'm also interested!

I have a 19" Viewsonic VX912 LCD and before when I used windows I noticed flickering in the picture while on 75Hz, so I went with 60Hz.

Now with OsX I have chosen 60Hz, but still get flickering.. and it's still there after changing to 75Hz.. Is it possible that it runs on 75Hz all the time?

I have a 8600GT.

 

Thanks! Hope this will be solved, the flickering is quite annoying

 

I have a GeForce 8600GT too and use a Samsung SyncMaster 913N via its VGA connector (via KVM too) on the same PC with:

OS X runs it at 1280 x1024 @ 75Hz 32 bit colour

 

Vista 64 runs it as 1280 x1024 @ 60Hz 32 bit colour by default (gives 72 and 75Hz as options)

 

Ubuntu 8.04 (Hardy Heron) runs it as 1280 x1024 @ 50Hz 32 bit colour by default (with 51Hz as an option)

with no flicker.... which proves that refresh rates have no meaning in the context of LCD displays see this site but the problem could be either using VGA rather than DVI if your LCD monitor is DVI based, or the LCD itself in terms of its response time - see here.

[zeba]

I have a GeForce 8600GT too and use a Samsung SyncMaster 913N via its VGA connector (via KVM too) on the same PC with:

OS X runs it at 1280 x1024 @ 75Hz 32 bit colour

 

Vista 64 runs it as 1280 x1024 @ 60Hz 32 bit colour by default (gives 72 and 75Hz as options)

 

Ubuntu 8.04 (Hardy Heron) runs it as 1280 x1024 @ 50Hz 32 bit colour by default (with 50Hz as an option)

with no flicker.... which proves that refresh rates have no meaning in the context of LCD displays see this site but the problem could be either using VGA rather than DVI if your LCD monitor is DVI based, or the LCD itself in terms of its response time - see here.

 

 

Ok!

Well thanks for the information, but I still think it's strange that I can notice flickering in Windows when switching from 60Hz to 75Hz :/

The LCD has a responsetime of 12ms, and has both DVI and VGA. Always used DVI.

As soon as I get home I will try with a dvi->vga adapter and see if there's any change when using a VGA cable.

 

thanks

[penestijeras]

Hi all,

 

Thank you for your responses. I wish 75hz, because the image flickering is smother... I can see the flickering with dark greys colous, like Adobe Lightroom interface... If I try low resolutions (like 1024*768 at 75hz) I can't see the flickering, the image is perfect... If I turn again to 1440*900 at 60hz again I see the image flickering...

 

I tried boot (f8) with "graphics mode" = "1440x900x32@75" but it does not work... It has again 60hz. Any idea?

 

Thank you all

[verdant]

Hi all,

 

Thank you for your responses. I wish 75hz, because the image flickering is smother... I can see the flickering with dark greys colous, like Adobe Lightroom interface... If I try low resolutions (like 1024*768 at 75hz) I can't see the flickering, the image is perfect... If I turn again to 1440*900 at 60hz again I see the image flickering...

 

I tried boot (f8) with "graphics mode" = "1440x900x32@75" but it does not work... It has again 60hz. Any idea?

 

Thank you all

 

@ penestijeras

@ zeba

 

Check this LCD flicker test site here..it may help isolate your flicker issues....

[zeba]

@ penestijeras

@ zeba

 

Check this LCD flicker test site here....it may help isolate your flicker issues....

 

Where...

[verdant]

Where...

 

Oops... sorry... link is fixed now in my original message....

[penestijeras]

(sorry I was out due my job)

 

Thanks a lot haxi. Your link is very useful. I will check it when I arrive home.

 

It is extrange because windows and linux show me well the refresh rate. I would like to use DVI rather than VGA, because the LCD has 2 inputs (DVI + VGA). Is it appreciable de quality difference from VGA - DVI for you?

 

I will inform you all about my experiences.

[verdant]

(sorry I was out due my job)

 

Thanks a lot haxi. Your link is very useful. I will check it when I arrive home.

 

It is extrange because windows and linux show me well the refresh rate. I would like to use DVI rather than VGA, because the LCD has 2 inputs (DVI + VGA). Is it appreciable de quality difference from VGA - DVI for you?

 

I will inform you all about my experiences.

 

I have noticed no quality drop with VGA on my LCD monitor to DVI on gaphics card

[penestijeras]

Hi Haxi,

 

I would like to thank you, because it works! It is connected via VGA and the quality is the same than DVI, but 75hz does not affect with any flickering. The image is smoth

 

I have test the quality with another twin hackintosh with the same LCD + graphic card and I can't appreciate differences. I have used SwitchresX software for custom sizes (the system does not detect my "special" resolution 1440x900x32 @ 75hz). I apply it and the image looks perfect!

 

Thanks to this great forum!