for 4K 60Hz over HDMI, you need a card with HDMI 2.0 support (late 2014+)

[chrisNova777]

the evolution of H.D.M.I.
refresh rate of a graphics card determines the "frames per second" speed of your graphics response..

to achieve 4K resolution at 60Hz refresh rate over HDMI, a graphics card with HDMI 2.0 or later support is generally required. HDMI 2.0 offers the necessary bandwidth to support this combination.

https://en.wikipedia.org/wiki/HDMI#Version_comparison

HDMI 1.4a: (March 4, 2010), only supports 4K at 24Hz (4096x2160) or 30Hz (3840x2160). this means all graphic cards made in between 2010 + 2014 will not support 4k @ 60hz

The GeForce GTX 660, 660 Ti, and other GTX 600 series cards can support 4K resolution (4096x2160) at 60Hz via the DisplayPort connection only

HDMI 2.0 (September 2013). It introduced key features such as support for 4K resolution at 60Hz and increased bandwidth to 18 Gbps, enabling smoother video and gaming experiences.

Key features of HDMI 2.0 include:
-Increased bandwidth: From 10.2 Gbps to 18 Gbps, allowing for higher resolution and frame rates.
-4K at 60Hz support: Enabled 4K resolution at 60 frames per second, improving visual quality.
-32 audio channels: Increased the number of supported audio channels.
-Dual video streams: Allowed for two separate video streams to be displayed on one screen.
-21:9 aspect ratio support: Provided wider aspect ratio for a more cinematic viewing experience.
-Backward compatibility: Designed to be compatible with earlier HDMI versions.
-Support for HDR (HDMI 2.0a): Introduced in April 2015, added support for High Dynamic Range (HDR) metadata, enhancing color and contrast.

The first graphics cards to support HDMI 2.0 were released in late 2014, following the release of the HDMI 2.0 specification in September 2013. Nvidia's GeForce GTX 970 and 980, based on the Maxwell architecture, were among the first to include HDMI 2.0 support. These cards, along with the GTX 960, 980 Ti, and Titan X, were released in late 2014 and early 2015.

HDMI 2.0a: (April 2015)
HDMI 2.0a, released in April 2015, is an update to the HDMI 2.0 specification that primarily focuses on adding support for High Dynamic Range (HDR) content. This enables TVs to display a wider range of colors and contrast, making images appear more realistic with brighter whites and deeper blacks.

the AMD Radeon RX 480 https://www.techpowerup.com/gpu-specs/radeon-rx-480.c2848 was one of the first graphics cards to feature HDMI 2.0b (Mar 2016 ) It was released in 2016 and was part of a new generation of GPUs that also included DisplayPort 1.3/1.4 and support for HDR content.

HDMI 2.1: (Nov 2017)
While HDMI 2.0 is sufficient for 4K 60Hz, HDMI 2.1 is needed for higher refresh rates like 4K 120Hz or 8K resolution.
This newer standard offers significantly higher bandwidth, enabling 4K 120Hz or even 8K resolutions.

The Nvidia GeForce RTX 30 series https://www.nvidia.com/en-us/geforce/graphics-cards/30-series/ was the first nvidia gpu to feature HDMI 2.1. Specifically, the RTX 3070, RTX 3080, and RTX 3090 were among the first graphics cards to implement the HDMI 2.1 standard, enabling higher resolutions, refresh rates, and bandwidth for gaming and other applications, according to Cable Matters and HDMI Licensing Administrator, Inc.. This allowed for features like 4K at 120Hz and 8K at 60Hz, as well as variable refresh rates.

The first Radeon GPUs to support HDMI 2.1 were the Radeon RX 6000 series https://en.wikipedia.org/wiki/Radeon_RX_6000_series, released in November 2020. Specifically, the RX 6800 and RX 6900 XT were among the first to feature this capability. This series utilizes AMD's RDNA 2 architecture, which is also found in the PlayStation 5 and Xbox Series X/S consoles, all of which support HDMI 2.1.

thats why it makes sense that The first popular consumer GPUs to support PCIe 4.0 were also the Nvidia GeForce RTX 30 series and the AMD Radeon RX 6000 series

[chrisNova777]

Dec 2002 (1.0)
May 2004 (1.1)
Aug 2005 (1.2)
Dec 2005 (1.2a)
Jun 2006 (1.3)
Nov 2006 (1.3a)
Jun 2009 (1.4)
Mar 2010 (1.4a)
Oct 2011 (1.4b)

Sep 2013 (2.0) <-- 4k 60hz support over hdmi
Apr 2015 (2.0a)
Mar 2016 (2.0b)

Nov 2017 (2.1) <-- 4K 120Hz support over hdmi
Feb 2022 (2.1a)
Aug 2023 (2.1b)
Jun 2025 (2.2)

also see my post here on the history of gpus
http://www.oldschooldaw.com/forums/index.php/topic,3840

[chrisNova777]

Apple first used DisplayPort via Thunderbolt for 4k displays.. not HDMI
The earliest Mac models to support 4K resolution via their built-in ports were the Mac Pro (Late 2013) and the MacBook Pro (Retina, Late 2013).

They supported 4K output through their Thunderbolt 2 ports, which are also DisplayPort 1.2 compatible. This allowed for connections to 4K displays via Mini DisplayPort to DisplayPort or Mini DisplayPort to HDMI adapters.

hence the thunderbolt to displayport adapters:
https://www.amazon.ca/StarTech-com-Thunderbolt-Dual-DisplayPort-Adapter/dp/B08KFMBQ21

below is some further information on displayPort versions:

DisplayPort 1.2 was released in January 2010. It was officially ratified by VESA in December 2009. This version significantly improved upon its predecessor, DisplayPort 1.1, by doubling the data rate and introducing new features like Multi-Stream Transport (MST) for daisy-chaining multiple monitors.

DisplayPort 1.2, introduced in 2010, significantly improved upon previous versions by doubling the data rate to 17.28 Gbit/s, enabling higher resolutions, refresh rates, and color depths. It also introduced features like Multi-Stream Transport (MST) for connecting multiple monitors and support for stereoscopic 3D.

DisplayPort 1.2 supports various refresh rates depending on the resolution. For example, it can handle 1080p at 240Hz, 1440p at 144Hz, and 4K at 75Hz. It also supports 5K resolution at 30Hz. DisplayPort 1.2's maximum total bandwidth is 21.6 Gbps, which enables these refresh rates.

Specific refresh rates supported by DisplayPort 1.2:
1080p (Full HD): Up to 240Hz.
1440p (Quad HD): Up to 165Hz.
4K (Ultra HD): Up to 75Hz.
5K: Up to 30Hz.

DisplayPort 1.2 also introduced features like support for multiple independent video streams (daisy-chaining), improved audio bitrates, and stereoscopic 3D. It also added support for the Mini DisplayPort connector.

DisplayPort 1.4 was introduced on March 1, 2016. It's a significant update building upon DisplayPort 1.3, offering features like Display Stream Compression (DSC), Forward Error Correction, and enhanced audio capabilities.

DisplayPort 1.4 supports a wide range of refresh rates and resolutions,
including 8K at 60Hz and 4K at 120Hz without compression.
With Display Stream Compression (DSC), it can achieve 8K at 60Hz with HDR and 4K at 144Hz.
It is also capable of supporting 1440p at 240Hz.

Specific Refresh Rates and Resolutions supported by displayPort 1.4:
8K: 7680x4320 @ 60Hz (with DSC)
5K: 5120x2880 @ 60Hz (without DSC)
4K: 3840x2160 @ 120Hz (without DSC), 144Hz (with DSC)
1440p: 2560x1440 @ 240Hz (without DSC)
1080p: 1920x1080 @ 240Hz

DisplayPort 1.4 also supports HDR and is backward compatible with older DisplayPort devices.