[hannes69]

Managed to do it, thanks! Feels good not being at the mercy of Nvidia's drivers anymore.

To output correctly I needed to set it up as YCbCr 4:4:4. RGB was messing up the range through HDMI (didn't use to before).

Glad it worked for you. I don´t have any experience with nvidia, with my AMD there´s no range problem and I´m using RGB for all presets.

Does anyone know of a calculator to show the expected frame drops/repeats based on the clock deviation percentage? Or what would be the formula? I tried "something" but the results made no sense and I suck at math!

I´ll try:
First a simple example. Let´s assume we have a movie with 30.000fps. Let´s assume we have NO clock deviation. Let´s furthermore assume that our real refresh rate is e.g. 28.000Hz. So within one second 30 frames SHOULD be displayed, but because of our wrong refresh rate of 28Hz only 28 frames CAN be displayed. The remaining 2 frames only can be DROPPED.
The other way round: If we have a real refresh rate of 32Hz, and we only have 30 frames, what has to be done? 2 frames of the 30 have to be repeaten to get 32 frames.
So we get "2 frames dropped/repeaten per second" or 1 frame dropped/repeaten in 0.5 seconds.
So the formula if we want the result in hours (1hour = 3600 seconds):

time of dropped/repeaten frames = 1 / (3600 * (real refresh rate - movie framerate)) ; result positive: repeaten frames / result negative: dropped frames.

Now we have to include the clock deviation. The former formula didn´t cover that. We have to replace the expression (real refresh rate - movie framerate) with (real refresh rate - ideal refresh rate).
And as formerly described: ideal refresh rate = movie framerate * (1+ clock deviation)

So whole of the formula:

time of dropped/repeaten frames = 1 / (3600 * (real refresh rate - movie framerate * (1 + clock deviation))) ; result positive: repeaten frames / result negative: dropped frames. Clock deviation can be positive or negative, use the right sign! Clock deviation is given in % in madvr! real refresh rate is in the first line of the OSD of madvr.

You may not get the same results as madvr due to roundings etc. but it should give similar numbers, in my case it works.

I just deleted my custom resolution for 23.976 and the deviation-% went out of whack. Previously it was ~0.00088% and now way over 0.02000%?!

Hm, here I have no idea. The clock deviation should be independent of the used resolution...

My .00001% deviation drops a frame every three and a half minutes. This doesn't make sense. The clock deviation can't be accurate.

It could be possible. Let´s take the above formula, take your given numbers and ask for your real refresh rate. I assume we are talking of 23.976fps movie that has to be played back with a 23.976Hz refresh rate. I take your clock devaition of -0.00001% and your "1 frame is dropped every 3,5 minutes".
I get a real refresh rate of 23.97126Hz. So even if you have a very small clock deviation of -0.00001% but you have a "bad" refresh rate of 23.97126Hz you get one frame drop every 3,5 minutes!
As i often described now: You don´t go for low clock deviation (you can´t influence that) and you don´t go for real refresh rates like 23,976Hz, 25.000Hz, 29.970Hz and so on...

What you need is a real refresh rate that takes into account your clock deviation.
Don´t get confused with lucky numbers!
Having almost no clock deviation doesn´t certainly mean you cannot get dropped or repeaten frames, because you can have a bad refresh rate that doesn´t match to you your low clock deviation.
Having a perfect refresh rate setting of e.g. 23.97602Hz doesn´t mean you cannot get dropped or repeaten frames, because you can have a high clock deviation that doesn´t match to your refresh rate.

Or mathematically described: The number of dropped/repeaten frames per time unit depends BOTH of clock deviation and the real refresh rate. What you can´t influence is the clock deviation, this is fix, but you can influence the real refresh rate. And the real refresh rate has to be set in such a way that it eliminates the clock deviation. And this can be achieved by custom resolutions.

I gave up on trying to describe custom resolutions in the guides I maintain. Two many variables can cause problems and DSPlayer has been less stable, too.

I understand that. The problem is by nature, the thing with custom resolutions and perfect refresh rate is kind of mathematic / scientific thing. And I know that most of the people in this world are at war with mathematics

Does anyone have a good link on custom resolutions? I'd rather provide a link with great detail than attempt to add this topic to an already packed tutorial. It is really only a tool for advanced users.

Sorry, I have no link or direct description in this matter.
I´m a little bit frustrated that I couldn´t describe it in a better way. I now spent some time here on this topic and until now ashlar seems to be the only one who has understood what I wanted to describe. Maybe it is compexer to understand than I realize or my English is too bad...
In my opinion it is not a VERY advanced topic. There´s some theory behind it, but in practice you only have to do some small calculations and use freeware tools like CRU utility.
For me personally it is way more complex to understand how something like NNEDI upscaling works or how to implement a debanding filter...: But here I have to admit that you can simply activate them in madvr without the need to know how it works...