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Screen tearing at 240fps @190hz with dyac+ enabled

Posted: 26 May 2022, 11:55
by kPhobos
Im using large VT 1508,

Wanted to sublimt a video, but Forums dont support .mov, uploaded it as a YouTube short, so you Can see for yourself.


Fps is constant 240, in aimlabs (wanted to use this for example due to simplicity of textures and visual clearity)

https://youtube.com/short/7IuiqEDLg4s

I’ve Been messing around with CRU for a bit, but cant Seem to find a good standpoint, i want the highest refresh rate, but also the most efficient dyac+ settings, so figured 190hz would give enough headroom for my large VT to get ris of tearing and artifacts, but i just cant Seem to find the Sweet spot

Monitor is benq XL2546

Any suggestions appreciated!

Re: Screen tearing at 240fps @190hz with dyac+ enabled

Posted: 27 May 2022, 18:47
by Chief Blur Buster
I've never said that QFT eliminates tearing unless you're using RTSS Scanline Sync

Are you using RTSS Scanline Sync for the tearingless VSYNC OFF techniques?

QFT does make it easier to hide tearing with RTSS Scanline Sync, because of a bigger VBI for VSYNC OFF tearlines to jitter inside unseen offscreen, at framerate=Hz. If so, please post your Scanline Sync settings and I can help you.

If not, remember your GPU load needs to be roughly ~50% or less at 190fps for tearingless VSYNC OFF to work reliably. If your goal is eliminating tearing at the lowest lag possible, you may have to adjust your refresh rate down (while increasing the QFT factor to maintain the low latency of lower refresh rates) -- until GPU load falls enough to allow reliable scanline sync.

Image

In this use case, the bigger the Vertical Total, the more room in the VBI to hide tearline jitter using scanline-based frame rate capping techniques. RTSS Scanline Sync steers to raster-precise VSYNC OFF in the blanking interval between refresh cycles, moving the tearlines off the top edge of the screen.

The bigger the Vertical Total (bigger VBI), the more room for erratic timings to still keep jittering tearlines hidden in the VBI. But it must be done simultaneously with extra software such as RTSS Scanline Sync or Special-K Latent Sync, both of which are raster-methods of steering VSYNC OFF tearlines to a precise position (such as offscreen).