2560 × 1440 vs 2560 × 1600
QHD 1440p against WQXGA, side by side.
2560×1600 renders 409,600 more pixels than 2560×1440 — 11% more. They differ in shape too: 2560×1440 is 16:9 while 2560×1600 is 16:10, so windows and video fit differently.
The 16:10 version adds 160 rows to the QHD footprint — welcome for documents and code, invisible in 16:9 video, which letterboxes. 2560×1600 lives mostly in premium laptops and tablets while 2560×1440 dominates desktop monitors, so in practice the choice is usually made by the device category, not by you.