"A 99th percentile frame time of 25 ms (milliseconds) means that 99% of all the frames are rendered within 25 ms" (c) back2gaming.com

Does this mean that although you have more fps in average by 30% with the 1800X, the game still feels smoother with the 1500X because with the latter CPU you have lower (=better) frametimes?

Does this mean that although you have more fps in average by 30% with the 1800X, the game still feels smoother with the 1500X because with the latter CPU you have lower (=better) frametimes?