What is the meaning behind the version numbers in HDMI and DisplayPort?

Bandwidth dictates maximum resolution

Our laptop specifications always indicate the supported versions of DisplayPort and HDMI. For standards where the version number covers multiple bandwidth levels, we either support the maximum available bandwidth or we explicitly list the bandwidth in gigabits per second (Gbps) in the spec sheet.

Based on the provided version and bandwidth information, the maximum supported resolutions and refresh rates can be determined from publicly available reference tables. Support is therefore not directly dependent on the laptop or the GPU but rather on the bandwidth available through HDMI or DisplayPort.

A comprehensive table listing the resolutions and refresh rates supported by different HDMI and DisplayPort versions can be found here:

• Maximum resolutions and refresh rates of HDMI and DisplayPort

For even more detailed information, refer to these Wikipedia resources:

• HDMI: Refresh Rate Limits for Common Resolutions
• DisplayPort: Refresh Rate Limits for Common Resolutions

By checking the bandwidth supported by the laptop’s port, users can find all necessary details regarding maximum resolutions, refresh rates, and color depth in these tables.

All additional information below is provided as background knowledge.

Version number is not always conclusive

In the past, HDMI and DisplayPort connections were relatively straightforward: the version number clearly indicated the supported bandwidth - and thus the maximum resolutions and refresh rates. This has changed with the current generations. Both HDMI 2.1 and DisplayPort 2.1 combine several possible expansion stages under one version number, which can differ significantly in terms of bandwidth.

For end customers, this means that the number after "HDMI" or "DisplayPort" is now only a rough guide and not a reliable indication of the actual performance of the connection. Only the specific bandwidth specification (e.g. 18, 32, 40 or 48 Gbps) reveals which monitor resolutions and refresh rates can be used in practice.

We will explain this in detail in the following sections.

HDMI 2.1

The allowed bandwidth of HDMI 2.1 ranges from 18 Gbps (minimum configuration) to 48 Gbps (maximum configuration). Most laptop manufacturers do not specify which version their models are equipped with.

In general, the following picture emerges:

• HDMI 2.1 from an Intel or AMD iGPU often only offers 18 Gbps. This only changed in 2025, when AMD iGPUs offered HDMI 2.1 with 32 Gbps for the first time.
• HDMI 2.1 from an NVIDIA GeForce RTX graphics card (since around the RTX 30 series), on the other hand, almost always offers a full 48 Gbps – the maximum expansion level of HDMI 2.1.

The lowest expansion level of 18 Gbps for HDMI 2.1 actually corresponds to the former maximum expansion level of HDMI 2.0. Thus, HDMI 2.1 for iGPUs is usually a pure rebranding and not a real upgrade compared to HDMI 2.0.

With 18 Gbps, 4K@60Hz is possible, but not 4K@120Hz or 4K@144Hz.

So, if a laptop manufacturer without a dedicated NVIDIA graphics card specified ‘HDMI 2.1’ without specifying a bandwidth or resolution, it was safe to assume that only 4K@60Hz was supported, depending on the CPU platform. For details, see the table below.

For XMG and SCHENKER, we have therefore been using the following scheme since the introduction of HDMI 2.1:

• If only 18 Gbps (4K@60Hz) is supported, then we declare HDMI 2.0 in the spec sheet.
• However, if the HDMI port supports 32 or even 48 Gbps with up to 4K@144Hz, we declare HDMI 2.1 and specify the exact bandwidth.

DisplayPort 2.1

Overview

DisplayPort 2.1 is the first DisplayPort version (since 1.0) where you can no longer directly deduce the bandwidth from the version number.

First, a brief history: DisplayPort 1.4a always required HBR3 with a total of 32.4 Gbps. This allows 4K@144Hz or 8K@30Hz to be operated without DSC (image compression). This was the gold standard for DisplayPort from around 2014.

However, DisplayPort 2.1 is now available in three versions:

• DisplayPort 2.1 with UHRB10 = 40 Gbps (DP40)
• DisplayPort 2.1 with UHRB13.5 = 54 Gbps (DP54)
• DisplayPort 2.1 with UHRB20 = 80 Gbps (DP80)

"DP40", "DP54" and "DP80" are official marketing designations that were assigned by the industry consortium VESA, which defines the DisplayPort standard, to facilitate the branding of cables. PCs and laptops have always offered either DP40 or they double up to DP80 - but the DP54 "mid-level" is indeed available in monitors and cables. A DP54 monitor can be operated on a PC/laptop with a DP80 output, but not on a DP40 output.

In contrast to HDMI 2.1, the following applies to DisplayPort 2.1: even the smallest configuration (40 Gbps) has more bandwidth than the largest configuration of the previous version: DisplayPort 1.4 had 32.4 Gbps, making DP 2.1 at least 20% ‘wider’ than DP 1.4.

(DisplayPort 2.0 existed largely only on paper and therefore does not require closer examination here. The three bandwidth levels of DisplayPort 2.1 were already introduced with DP 2.0.)

The maximum resolution and refresh rate increase with bandwidth, depending also on the colour depth (8-bit or 10-bit) and DSC compression. For example, UHBR13.5 already allows 8K@60Hz, but UHBR10 (DP40) does not. Thus, when buying laptops, graphics cards and cables, it is important to pay attention to which DisplayPort version is supported.

Which CPU and GPU platforms support which bandwidth?

The following table shows the HDMI and DisplayPort bandwidths that can be expected with common CPU and GPU platforms. This can be presented in fairly general terms, as the bandwidth of the monitor connection is largely determined by the respective platform and also specified by its manufacturer.

Please note:

• As mentioned above, ‘Gbps’ stands for ‘gigabits per second’ (not to be confused with gigabytes per second). The higher the bandwidth in Gbps, the higher the maximum achievable monitor resolutions, refresh rates and colour depths. Corresponding reference tables are linked above in the article.
• DisplayPort signals can be output in laptops via both Mini DisplayPort and USB-C (including USB4 and Thunderbolt). The output format does not change the bandwidth provided by the platform.
• Some laptops have additional USB-C ports via daughter boards (smaller PCBs, not the mainboard). These ports often offer only reduced DisplayPort bandwidth (e.g. DP 1.4), while the primary port directly on the SoC provides full performance (e.g. DP40 or DP80). Please refer to the information in our data sheet for each respective laptop model.
• Sometimes CPU manufacturers specify certain bandwidths or protocol versions in their data sheets or marketing materials that would technically be possible but are not directly supported by the CPU or iGPU in practice. Instead, they require additional components called "re-timers" which convert and amplify signal, e.g. convert a native DP1.4 signal from the iGPU to an HDMI 2.1 signal, instead of using the native HDMI 2.0 signal from the iGPU directly. However, the use of such solutions means additional effort, higher costs and potential risks in terms of signal quality, compatibility and validation - which is why in reality these options are practically never implemented by laptop manufacturers. Our table above therefore reflects the actual market situation as found in 99% of all laptops.
• In NVIDIA, "Board 1" and "Board 2" are NVIDIA's two different reference layouts for NVIDIA GeForce RTX laptop GPUs. The DisplayPort bandwidth specified by NVIDIA differs between the "large" and "small" layouts – see table above. Formally, NVIDIA also only requires a smaller HDMI bandwidth (here: 40 Gbps) for HDMI in Board 2. In practice, however, there is no available technical solution for a 40 Gbps HDMI level, so a solution with 48 Gbps is used instead, which means that the actual HDMI bandwidth for Board 1 and Board 2 ends up being identical.

Distinction between iGPU and dGPU connection

In our data sheets, we also indicate whether a port is connected to the iGPU or the dGPU.

• Ports on the iGPU are ideal for office work and energy-saving operation, but can also be used for gaming via NVIDIA Optimus.
• Ports on the dGPU are particularly suitable for especially fast gaming (higher FPS, lower latency), VR headsets or monitors with particularly high resolutions (such as 8K via DP80).

It is therefore not always necessary to choose the "strongest" connection: if the iGPU port provides sufficient bandwidth for your monitor, you will save power and possibly reduce the fan noise in idle.

Summary

When finding a monitor for your laptop, do not only pay attention to the version number. Instead, check also the actual bandwidth provided. First, check your monitor's HDMI or DisplayPort requirements and compare them with the reference tables and the information in our data sheets. Also consider whether you should connect your monitor to the iGPU or the dGPU for a better balance between efficiency and performance.

Please also refer to the following articles:

• How can I set a program or game to run on either the iGPU or the dGPU?
• What are the differences between NVIDIA G-SYNC, AMD FreeSync and Intel Adaptive Sync?
• Which XMG laptops are compatible with VR headsets?
• My external monitor does not work reliably
• Short battery life in gaming laptops (2025)

If you have any further questions on this topic, please contact us.