Custom Resolution Utility (CRU)

[ToastyX]

(11-09-2023 06:09 PM)opa99 Wrote:  My challenge has been that in CRU the maximum Hertz is always 60 for these high resolutions (at least what I have been able to achieve), and then I later change the Hertz in Nvidia settings.

What do you mean? Where is the maximum you are seeing, and where are you changing the Hz in NVIDIA settings?

(11-09-2023 06:09 PM)opa99 Wrote:  I have not put a lot of thought into these clock or blanking values, but instead used the "Automatic HDTV" presets, since I can see that those change with the refresh rate. Would there be a source where I could read and learn what these "do" and how I should change them?
Earlier I did check Monitortests main page for the explanations, but what I can understand from there is, that with modern displays (I understand this also includes TVs), I can reduce blanking, but what I do not understand is why I would like to reduce it? Thank you for bringing up the audio requirements for the blanking, this I had not understood earlier.

The blanking parameters basically just give some break time between lines and frames, which was more important for CRT monitors because they needed time to move the electron guns. HDMI uses the blanking periods to transmit audio because that portion of the signal isn't visible. "Automatic HDTV" takes care of that for TV resolutions listed in the CTA-861 standard, but for non-TV resolutions, it's the same as "Automatic PC" which uses the CVT reduced blanking standard. The blanking can be reduced further to reduce the bandwidth if you're close to a pixel clock limit, which is the total number of pixels per second. Otherwise it doesn't really matter.

(11-09-2023 06:09 PM)opa99 Wrote:  Also what is a bit puzzling is the max bandwidth settings in extension blocks, I do not fully understand how I should set them. I have HDMI 2.1 connectors (and cable) on both ends, so I would assume that the generic 600 MHz maximum is not the limit, but for some reason that seems to work for me, even though with the calculators it should not (for 3840x1500 @120hz, with HDR)... The bandwidth limit on my GPU is 48 Gbps and on the TV (receiving) the limit is 40 Gbps, but I have no idea what that would be in TMDS limit, or if that is even relevant for HDMI 2.1.

So any link where I could learn more on the pixel clocks / blanking / extension block details would be appreciated.

You don't need to change any of that. The maximum TMDS character rate for HDMI 2.x should be no more than 600 Mcsc, and that only applies to TMDS signals. FRL signals use the maximum FRL rate, which should already be set to 40 Gbps as reported by the TV. HDMI is a proprietary standard and isn't freely available, so it's hard to find information about HDMI 2.x online. The CTA-861 extension block and data blocks are defined in the CTA-861 standard available here: https://shop.cta.tech/products/a-dtv-pro...-cta-861-i