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My monitor seems to be maxed out at 1440 x 1080 @102HZ with CVT reduced blanking which has a horizontal refresh rate of around 117KHz which is my monitor's max but is it possible to obtain a higher refresh rate by tweaking anything in the timings settings?

Eight Bites wrote: ↑

21 May 2021, 18:12

My monitor seems to be maxed out at 1440 x 1080 @102HZ with CVT reduced blanking which has a horizontal refresh rate of around 117KHz which is my monitor's max but is it possible to obtain a higher refresh rate by tweaking anything in the timings settings?

Your limiting factor is probably your horizontal scanrate. Try reducing your vertical resolution to get a higher Hz. Scale the Vertical Total proportionally.

Your 117KHz scan rate is 117000 pixel rows per second. That means your Vertical Total is probably approximately 1147 or very close to it (117000 divided by 102Hz refresh rate).

Naturally, lowering your vertical resolution gives you more refresh rate headroom. You may need to increase VBI size at a higher refresh rate to make sure that the VBI is the same on-the-clock time. Currently if you are Vertical Total 1147, that means you’re using (1147-1080)/1147 of 1/102 second in VBI time. Replace 1147 with your current vertical total, 1080 with your vertical resolution, and 102 with your current refresh rate. Whatever new numbers you do, make sure your time (in microseconds or milliseconds) does not shrink. Naturally this may require a slightly larger vertical total at higher refresh rates, to compensate.

You may hit some electronic cops (firmware based Out of Range alarms) but as long as you don’t go under current VBI time (and the horizontal equivalent HBI), and you don’t exceed your scanrate specification.

You can also try shrinking your vertical total or VBI time too, but that can be risky on a CRT, especially if you’ve got artifacts like curving / excess brightness at edge / compressed linearity / folding at the top or bottom edge. Or the more harmless vertical compress behavior.