It's very tough and very lottery-dependant on these units. Experiment with things like color depth changes, porch changes, etc.
Try increasing Horizontal Back Porch, to give the monitor more time to initialize a new pixel row, so it's not too late at refreshing the scanlines. If you don't have bandwidth headroom, try reducing Horizontal Back Porch when increasing Horizontal Front Porch. This gives a new pixel row a few more microseconds to begin to initialize, and increases likelihood that the monitor will successfully refresh a row of pixels with fewer side effects.Amatureweeb wrote: ↑19 Jun 2023, 02:41- In most OC modes image is off-center to the right by few pixels. Can I offset this?
Unfortunately, no guarantees. But it helps if you visualize the signal like this layout:
The pixel row is pushed to the GPU output at (1/horizontal refresh rate)th of a second, at an aspirational one pixel-per-Pixel Clock constant rate, and sometimes the code in the monitor scaler/TCON/firmware needs more time to begin to initialize a new pixel row. This can be very problematic when trying to increase time between pixel rows, forces the monitor to refresh the pixel row faster, in a "microseconds tradeoff" basis, but you can experiment by shrinking/expanding certain porches to de-glitch certain things.
Larger Back Porches usually are helpful, even at the expense of Front Porch, to give the display more time to successfully begin refreshing a new pixel row, as the pixels are sprayed out of the GPU output like a book (left-to-right, top-to-bottom), and understanding the temporal tradeoffs in the porches is very helpful to skilled overclocking.
Disable as much processing as possible (1:1 scaling, no overdrive, default color profile, instant mode, etc) to reduce any processing cycles consumed in the scaler/TCON. Sometimes your glitch will be caused by circuits in the LCD itself (e.g. malfunctioning shift registers) and the best you can do is to reduce the bandwidth by lowering resolutions. Whether it's things like 1600x900 (windowboxing) or 1920x720 (letterboxing), as it's a game of number of pixels/second in your bandwidth budget. Lowering bit depth to 6 bits per channel can help in many ways too.
It's impressive that a very old XL2420T from more than ten years ago, can do refresh rates more than some monitors today, through these overclock tricks. But sometimes there's only so much overclocking tricks you can do, before it just glitches too much;
