On my computer, I cannot drive my 1440p240hz OLED display with HDR. HDR takes the requirement from 25 Gigabit to 30 Gigabits, just over DP1.4's capabilities: https://linustechtips.com/topic/729232-guide-to-display-cabl...

Like you say, not that much difference, but enough to make DP1.4 not an option