Maximum Video Bandwidth of DP Alt Mode?

[prawn432]

Hello,

I'm currently looking to purchase a high resolution/refresh rate monitor (2560x1440, 180Hz) and I was wondering if my notebook's USB-C DP Alt Mode is capable of running the monitor at full capacity? I will be connecting it through a docking station that has a full size DP 1.4 port.

[Sneha_01]

Hi @prawn432 

Welcome to HP Support Community.

Thank you for posting your query, I will be glad to help you.

When you're looking to connect a 2560x1440 resolution monitor with 180Hz refresh rate via USB-C with DP Alt Mode, it's important to check if the bandwidth provided by your USB-C port is sufficient to handle that resolution and refresh rate.

Maximum Video Bandwidth of DP Alt Mode

USB-C with DisplayPort Alternate Mode (DP Alt Mode) supports different versions of DisplayPort standards, which in turn define the maximum bandwidth available for video output. The most relevant standards here are:

• DisplayPort 1.2 over USB-C (DP Alt Mode):
  • Maximum bandwidth: 17.28 Gbps.
  • Can comfortably support 2560x1440 at 180Hz, especially if you're using 8-bit color depth. Higher color depths (like 10-bit) might push the bandwidth limits at higher refresh rates.
• DisplayPort 1.4 over USB-C (DP Alt Mode):
  • Maximum bandwidth: 25.92 Gbps.
  • This is more than enough for 2560x1440 at 180Hz, even at 10-bit color (which would typically require more bandwidth than 8-bit color). The additional bandwidth in DP 1.4 also allows for support of higher resolutions, refresh rates, and even higher color depths or HDR.

Can DP Alt Mode Support 2560x1440 at 180Hz?

With DisplayPort 1.2: Yes, DP 1.2 over USB-C should handle 2560x1440 at 180Hz if you're using 8-bit color. If you're aiming for 10-bit color or HDR, you may be pushing the limits of DP 1.2, but it’s generally manageable at this resolution and refresh rate.

With DisplayPort 1.4: Absolutely, DP 1.4 will handle the resolution and refresh rate easily, even with higher color depths or HDR. It's a much better option for higher performance and future-proofing.

Docking Station Considerations

If you're using a docking station with a full-size DisplayPort 1.4 port, your main concern is the USB-C port on your laptop. Ensure that your laptop's USB-C port supports DP 1.4 or at least DP 1.2. If it only supports DP 1.1 or older versions, you may encounter limitations in terms of refresh rate and resolution.

If the docking station has a full-size DisplayPort 1.4 and you're connecting via USB-C, this should provide the maximum bandwidth for your monitor to run at 2560x1440 at 180Hz with no issues, assuming your laptop’s USB-C is up to the task.

I hope this helps.

Take care and have a good day.

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Sneha_01

HP Support