How to get 4k@120hz with a Nvidia RTX 3080 and the Sony x900H TV

I recently connected my gaming PC to my Sony TV and wanted to get 4k@120hz working. After piecing together a few forum posts and getting it working I thought I’d put all together here. First we need to setup the Sony TV:

  • Using you TV remote go to Settings then the first option “Watching TV”
  • Go down to “External inputs” then “HDMI signal format”
  • The HDMI ports 3 and 4 are the only ones with 4k@120hz capability so go to the HDMI port the PC will be connected to and enable “Enhanced format” (mine is connected to HDMI 4)
  • Switch to the HDMI port your PC is connected to.
  • Go back to the main settings page and now go to “Display & Sound”.
  • Go to “Picture” and for “Picture mode” set to “Game”. This is important to get 120hz working.

One note on my setup is I connected my PC directly to my TV instead of my receiver because of the Game mode I have to set my HDMI 4 port to. The HDMI port 3 on my TV is set to enhanced format and used as eARC as well and that port is set to “standard”. Next step is to connect the HDMI cable but you must make sure it is a certified ultra high speed HDMI cable. Technically there is no such this as a “HDMI 2.1” cable. Right now, this is one of the very few cables that are certified ultra high speed (affiliate link). I connected this cable from my HDMI 4 port on my TV to my only HDMI port on my gaming PC with the Nvidia RTX 3080. On the PC there’s a few things you need to adjust:

  • Go to the Nvidia Control Panel (you can right click on the Nvidia taskbar icon)
  • Under Display -> Resolution, select the Sony TV display.
  • Under “Choose the Resolution”, scroll down the options until you see “PC”. There are technically two sections here, “Ultra HD, HD, SD” and “PC”. We need to set the PC to 4k mode in PC mode NOT “Ultra HD, HD, SD” mode.
  • Set resolution to “3840 x 2160”. If this is done right, you will see under “Refresh Rate” two options: 100hz and 120hz. Select 120hz.
  • TV should blink and you’ll see an image then click “Apply” to save the changes.
  • If you don’t see an image don’t worry, the PC will revert the changes after 15 seconds. Double check your TV settings but also make sure you are using a certified ultra high speed HDMI cable. This will NOT work with one that is certified. This is a common issue I saw on the forums.
  • To enable surround sound, right click on the volume icon in the taskbar and select “Speaker setup” and select your preferred speaker setup (5.1 or 7.1).
  • You also will need to enable HDR mode by right clicking on your desktop and selecting “Display Settings” (I’m on Windows 10). Select the Sony TV and enable “Use HDR”. You can double check HDR is working by hitting the “Display” button on your Sony remote at the bottom. It should say “3840 x 2160 4K 16:9 HDR (HDR10)”

That’s it! I know it all seems convoluted but that’s the price you pay with new tech. Another note here is Windows is HDR10 only. You cannot enable Dolby Vision. If you do then the signal wont work. Not an issue if you only play video games as they are all HDR format but playing Blu-ray movies with Dolby Vision is a no-go. If you have an questions, feel free to leave a comment.

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