Trying to get 60hz 4:4:4 from 980ti to my new 4k tv via HDMI (mac hardware) Shrunk image, no 60hz option, etc.

[cheezgratr]

I'm running a  MacPro 3.1 (2008 cheese grater, not a Hackintosh), but I was told you guys know more about Nvidia drivers and such than anyone else, and I got the drivers I'm running from this site.

 

OSX 10.11.6 (last OS officially supported for my machine

Installed Nvidia driver listed on this site for my exact build:  Nvidia Web Driver - 346.03.15f11 --> build 15G18013 (thanks to BreBo)

Confirmed that I am using this driver (not mac)

 

Just got a used 980Ti:

3 DisplayPort 1.2

1 HDMI 2.0

 

And a new TCL 65S405 4k TV

3 HDMI 2.0

 

Rtings.com did extensive tests on the tv, and says it will do 4k 60hz 4:4:4 with a caveat about it needing to be in PC mode which is forced when it sees PC input:

Rtings.com notes on inputs for this set

I'm a bit confused by that as I've been told HDMI 2.0 bandwidth isn't enough to cover 4k 40hz 4:4:4, and that's the only inputs the TV has.

 

Unfortunately, I'm not even getting the 4k part right at the moment as I have no Nvidia Control Panel (PC only), and the Display options in System Preferences list only 30hz and 24hz as options.  I can get the correct resolution as it is one of the options, but it is signigicantly shrunk on the screen with several inches of black on all sides.  Not sure if it's an underscan issue, but there are no controls for under/overscan... or anything else.

 

I can't speak for the HDMI cable.  Maybe it's not up to HDMI 2.0 specs, but would that explain the shurnk image or lack of controls.  Seems like I'm missing something on the control side.  Do all mac 980ti users have to use SwitchResX or something similar to gain controls?  Or is there something else entirely causing the pic to shrink?  If so, I still see no controls for 60hz... haven't gotten to the 4:4:4 part yet as I'm stuck trying to get the right size image.

 

I do remember having this same issue years ago on same machine, but original stock video card, and a 1080p tv.  I finally gave up and ran out vga, and SwitchResX was then able to define the right resolution.  The tv only has HDMI 2.0 for inputs, so , that's not an option here (plus, I don't think VGA has specs high enough anyway).

 

I'll be doing some video editing, so open to any solution that gives me the most accurate possible monitoring.  For instance, if there is a bandwidth issue for 4k 60hz 4:4:4, would it be possible to get around that by doing something like splitting the screen in half, and using 2 outputs on the 980ti to feed the two halves simultaneously?  Seems I've heard of 5k display owners doing something similar, and I've only got one display, so should be power to spare in the 980ti.

[cheezgratr]

Easy fix scaling how, though?  SwitchResX?  No scaling options at all in System Prefs.

 

Also, I know it's doable if only because of all the chatter out there about folks doing it.

 

Have you tried outputting via Display Port to ACTIVE HDMI 2.0 converter to high speed cable to TV?  I think I've read somewhere that some folks were saying they could only get 4k 30 hz out of the HDMI port due to a built in limitation on the card, but that doing the conversion using an (ACTIVE) converter, they got 4k 60hz.

 

EDIT:  Just ordered a new cable.  Reviews seemed to agree that Monoprice's best (not fiber optic) cable did 60hz 4k 4:4:4 where many others failed... including a couple reviews from 1080ti users, though they may have been on PC.  If so, though, it's got to be just a software issue, and therefore fixable... I'd think.

Edited May 23, 2018 by cheezgratr