Can't get PC to display 4K60Hz over HDMI 2.0 with cable that works perfectly with my Xbox One X. Do I need to buy a premium one?

[Rowza245]

Really not sure what i'm doing wrong here as i'm usually quite techy, but my PC refuses to output 4K60 to my TV.

 

Both devices are HDMI 2.0 (AMD RX5700 XT on a Windows 10 PC running latest drivers (20.2.2) to a Kogan 55" TV - if you look under the specification tab on the link here it shows all 4 HDMI ports are 2.0 and specifically says that it supports 3840 x 2160 @ 60Hz through HDMI: https://www.kogan.com/au/buy/kogan-55-smart-hdr-4k-led-tv-android-tv-series-9-xu9210/ ) 

I've tested it not connected to any other displays, tried to force it though custom resolutions in AMD Radeon, tried to change the refresh rate in the display adaptor properties (dosn't show anything higher than 30Hz), looked extensively in my TV settings turning stuff like game mode on and even played around with the different pixel format modes with no luck (colour depth always snaps back to 8 bit but that's expected).

At first I thought it was the cable. I had read on many sites that a standard high speed HDMI cable should be able to handle it but reading further after buying a 5m (~16.4') cheapo one i've seen conflicting info that I might need a premium one that is properly rated for 18Gbps, especially after 3m of length. 

To test this I used the samecord with my Xbox One X and had no trouble at all - looking under TV details in settings says the TV supports 4K60 with HDR which it's definitely outputting - opening Netflix pops up the notification on my TV that it's using Dolby vision. I then moved my PC closer to my TV and used the original cable that came with my Xbox but still no dice. 

My question is that if the Xbox is fine with the cables why won't they work with my PC? Is there something that i'm just missing? I really don't want to have to splurge to get a premium cable if i don't have to as it costs literally 3x the price.

Any help would be much appreciated - Thanks  

[Zando_]

Shouldn't need a premium cable, I'm using a basic HDMI cable with an RVII and I forget what model LG TV, it does 4K60 HDR over that just fine . IDK what would cause an issue like this, though my cable is a shorter one. 5m is a rather long HDMI cable, perhaps it is an issue with the cheaper one? I think mine is only 1-1.5m or something. 

[Rowza245]

Yeah i was thinking it was the length at first myself, but as I mentioned i also tried the one that originally came with the xbox which is only about 1.5-2m so i'm at a loss as to whats going on really. Thinking back I've also had a 4k monitor hooked up to it in the past with no problems so i'm guessing that it might have something to do with the TV, although why would the xbox work and the pc not? Weird 

[Zando_]

3 minutes ago, Rowza245 said:

Yeah i was thinking it was the length at first myself, but as I mentioned i also tried the one that originally came with the xbox which is only about 1.5-2m so i'm at a loss as to whats going on really. Thinking back I've also had a 4k monitor hooked up to it in the past with no problems so i'm guessing that it might have something to do with the TV, although why would the xbox work and the pc not? Weird 

Hmmmmmm... my TV has some ultra deep color thing I have to enable for 4K60 HDR to work, but that's it. 

get a premium cable from Amazon and just return it if it doesn't make a difference

[Rowza245]

22 minutes ago, Zando Bob said:

Hmmmmmm... my TV has some ultra deep color thing I have to enable for 4K60 HDR to work, but that's it. 

get a premium cable from Amazon and just return it if it doesn't make a difference

Dove into the TV settings again to make sure I hadn't missed anything and found the fix! I saw a setting for HDMI EDID version where you could select either auto, 1.4 or 2.0. Tried to just switch it from auto to 2.0 earlier and it didn't do anything, but switching to 1.4 and then switching to 2.0 did the trick. It was hidden away in the android TV settings for some reason too so thanks Google for making that 10x more effort than it had to be  Thanks for your help