Here you go:

What Is HDMI 2.1?: An Overview

HDMI 2.1 is arguably one of the most significant upgrades to the HDMI standard. Originally announced in November 2017, HDMI 2.1 significantly increases the maximum bandwidth capability of HDMI up to 48Gbps, and even more when compression is used.

www.rtings.com

Nice chart!

 

thats a solid chart but its for HDMI 2.1 and doesn't say which of those resolutions will be DSC?

 

3840*2160*30*120= ~29.86Gbps

That's well past the actual data rate (~25.92Gbps) of HBR3 DP 1.4 without DSC.

 

so back to the original question, what is the max refresh rate I can run 4K HDR content at with DP 1.4 and not use DSC

I understand that 12bit color is not attainable but what is attainable?

 

I think 2160p@120hz 8bit color, thought I remember a monitor review where the reviewer stated he was doing 2160p@144hz with 8bit without DSC. 10bit and it drops to 90ish from what I remember.

Edit: Found this post with several tables/calculators.

https://linustechtips.com/topic/729232-guide-to-display-cables-adapters-v2/?section=calc

The last one, Data Rate / Maximum Refresh Frequency Calculator is the one to look at. According to that calculator 97.4hz should be the theoretical max refresh rate for 2160p at 10bit. You may need to create a custom resolution with your display driver to get those numbers, as Windows will probably just give you 60hz or 75hz as options.

 

Thanks @Melcar

looks like for 3840x2160 resolution its the following when connected via DP 1.4

• 120.4hz for max refresh frequency with no compression at 8b
• 97.4hz for max refresh frequency with no compression at 10b
• 81.8hz for max refresh frequeny with no compression at 12b

That tool doesn't mention HDR though and I dont know which timing format is correct either.

 

That tool doesn't mention HDR though

It's implicit in the bits per pixel. Anything over 8-bits per channel is HDR. Most HDR content works perfectly fine with 10bpc.

 

CVT-R2 is I think the "safe" default to assume with PC monitors. Could be wrong, as I'm just parroting what I have read in other forums.

 

I have a 27UCDM and a 5090 I caant get the DP2.1 to work at more than 4k120hz without DSC even thou that I read that it can do 4K240hz full colour without DSC, something is not right I even tried 3 cables the DP80cable that came with the monitor a Club3D and a Silkland

edit: Manged to get working by DDUing the drivers and then doing clean install on Nvidia installer. This was the last thing I done lol I was going nuts DDU didnt much sence to me maybe because I had a 4090 before, this with the DP80 cable from the monitor so iam returning the other cables I bought.