The S4 and S6 run on the same navigation hardware: LDS lidar, high-precision
mapping, multi-floor maps, and zone or room-specific cleaning are identical on both.
So this isn’t really a question of which one is “smarter.” It’s
about what happens after the vacuuming. The S6 adds a 160 ml water
tank and a mopping pad that the S4 doesn’t have at all, runs at 50 dBA
against the S4’s 68 dBA, and recharges in 150 minutes instead of
240. Suction power (2,000 Pa on both) and dustbin size (480 ml vs.
420 ml) are close enough not to matter.
If mopping isn’t something you need, the S4 vacuums exactly as well as the
S6 does. If it is, or if a noticeably quieter and faster-charging robot matters to
you, the S6 is the same core robot with those gaps closed.
Roborock lineup, suction power (Pa)
S6
S4
Roborock lineup, noise level (dBA), lower is better
S6
S4
…