NVIDIA Pixel Clock Patcher

[niciuffo]

(11-03-2015 04:20 PM)ToastyX Wrote:  

ToastyX Wrote:What happens when you try to go over 165 MHz? Is the driver not allowing it ("test failed" message) or is the TV not displaying it?

When going over the 165MHz limit, the TV just displays this message:


The nVidia CP doesn't say anything about the resolution not being valid.
To add to this, a pixel clock of 163.3500MHz works, but a value of 165.8250MHz does not.

ToastyX Wrote:Hardware limits are not exact like that. It's usually possible to go higher than 165 MHz unless there's a new driver limit that I don't know about. If it's a driver limit, 165.00 MHz will work but 165.01 MHz will not. If the TV has a pixel clock limit, it won't be exact like that.

I tried messing with the "Total pixels" values to test at which point the TV refuses to accept the signal (I changed the Horizontal values).
Up to this point, the TV accepts the resolution:

At this point, the TV refuses it ("Mode not supported"):

ToastyX Wrote:Those values are impossible because the total includes the active + front porch + sync width. It's probably reducing the sync width without telling you.

That might be true. One thing I should note, which I found weird. This is the default resolution (1920x1080@60Hz), seen by the TV's OSD:

And this is the custom (1920x1080@75Hz, settings in my last post) resolution:

Could this be a bug on the TV side, or is it really only displaying that amount of pixels? The pixel clock was still below 165MHz, so I don't know why it would not display the full 1080p image.
Is there a test I can do to verify the resolution?

ToastyX Wrote:Technically, 0 front porch values are possible, but the driver might not be handling it correctly. The TV should tell you what refresh rate it's actually receiving in the OSD.

I tried setting the front porch values to 0, and the sync width values to 1 (can't set them to 0). Total pixels: 2020x1089.
I am able to test a resolution with a pixel clock higher than 165MHz. I tired setting the refresh rate to 120Hz, and the TV accepted the signal, although the OSD still said "1440x900@75Hz".
Moving the mouse around, I can confirm that it was not running at 120Hz.

ToastyX Wrote:The only way to reduce the pixel clock without reducing the refresh rate is to reduce the totals. The totals include the front porch and sync width, so reducing those might allow you to reduce the totals further.

I tried reducing those values to 1, to remain within the 165MHz limit, and the max stable refresh rate was 77Hz I think. It was very unstable though, every ~15 seconds the TV would display a black screen for a couple of seconds.