HDMI 2.1 vs DisplayPort 1.4 for 144 Hz gaming

AnswerIt depends

At 1440p 144 Hz they're equal: both carry it uncompressed, even in 10-bit. At 4K 144 Hz, HDMI 2.1 at 48 Gbps carries 10-bit uncompressed (39.19 Gbps), while DisplayPort 1.4 needs DSC. DSC is visually lossless and supported by most 4K 144 Hz monitors and recent GPUs, so in practice both work. On a monitor, DisplayPort is still the safer default because adaptive sync support on it is more consistent.

1440p 144 Hz, 10-bit

Link	Needs	Has	Result
HDMI 2.0	17.60 Gbps	14.40 Gbps	Too much
DP 1.4	17.60 Gbps	25.92 Gbps	Fits
HDMI 2.1 40G	17.60 Gbps	35.56 Gbps	Fits
HDMI 2.1 48G	17.60 Gbps	42.67 Gbps	Fits

How the numbers are worked out

Reduced-blanking timing (VESA CVT-R2)

2560×1440 active → 2640 × 1543 total pixels per frame

2640 × 1543 × 144 Hz = 586.59 MHz pixel clock

586.59 MHz × 30.0 bits per pixel = 17.60 Gbps

10-bit colour, full RGB/4:4:4: 3 × 10 = 30.0 bits per pixel.

"Has" is the link's usable rate after line coding. DSC is modelled as up to 3:1 compression. Full method.

4K 144 Hz, 10-bit

Link	Needs	Has	Result
DP 1.4	39.19 Gbps13.06 with DSC	25.92 Gbps	With DSC
HDMI 2.1 40G	39.19 Gbps13.06 with DSC	35.56 Gbps	With DSC
HDMI 2.1 48G	39.19 Gbps	42.67 Gbps	Fits
DP 2.1 UHBR13.5	39.19 Gbps	52.22 Gbps	Fits

1440p 240 Hz, 10-bit

Link	Needs	Has	Result
DP 1.4	30.77 Gbps10.26 with DSC	25.92 Gbps	With DSC
HDMI 2.1 40G	30.77 Gbps	35.56 Gbps	Fits
HDMI 2.1 48G	30.77 Gbps	42.67 Gbps	Fits

The practical picture

1440p up to 165 Hz: any DisplayPort 1.4 cable, or HDMI 2.1. HDMI 2.0 manages 1440p 144 Hz only in 8-bit (14.08 of 14.4 Gbps).
4K 120–144 Hz: HDMI 2.1 with an Ultra High Speed cable, or DisplayPort 1.4 with DSC and a DP8K-certified cable.
4K 240 Hz: DisplayPort 1.4 or HDMI 2.1 with DSC, or DisplayPort 2.1 UHBR20 uncompressed.

Many gaming monitors have both ports but give the DisplayPort input the highest refresh rate and the widest VRR range. Check the manual: some 4K 144 Hz monitors limit their HDMI 2.1 input to 120 Hz.