Yes, older Windows versions can display 144Hz on a current 2560x1440 screen.
Yes, older Windows versions can display 144Hz on a current 2560x1440 screen.
When the graphics card is compatible, you might encounter some difficulties with 98, 2000 and XP systems, though Windows 7 would work fine.
Even the simplest options can back it up if a developer creates a driver for it.