It's just frametimes. Framerates aren't the best measure of smoothness/consistency. I imagine the consoles generally have good frame limiter solutions onboard, while on PC, you have to kind of know which program to use.
Here's an example with The Witcher 3, taken from Durante's PC Gamer article titled 'The Alchemy of Smoothness':
This last image represents the most consistent and smooth 30fps possible. This is the 'console-like' smoothness people are talking about. See how using a different program(RTSS) is preferable to using the in-game limiter?
So just to be perfectly clear: the way to achieve the best framepacing with minimal input lag at a locked 30 FPS is to:
Enable:
Rivatuner Statistics Server 30 FPS lock
Borderless Windowed for real triple buffering
Disable:
In-game triple buffering
In-game V-sync
In-game FPS limiter
Is that correct?