The sliders' drives have quite diverse speeds. The X-MOTOR is the strongest one - it's the only drive that can work vertically, but it comes with the price of speed. It can go only 5 cm/s (c.a. 2 in/s). The STEPPER DRIVE is the most versatile - 0.4 m/s (c.a. 16 in/s) is enough for most applications. The fastest one - the SERVO DRIVE - is capable of really high speeds, up to 2 m/s (c.a. 6.5 ft/s), but is suitable only for long setups. It requires about 1m to accelerate to the full speed, so it cannot achieve its full speed on a slider shorter than 2 m.
The maximum sound level values in the table above might be misleading, as the speeds of the drives vary significantly. By analysing the chart you will find, that the SERVO DRIVE is the loudest, but only at its highest speed. The X-MOTOR is about 40 dB at 25-50 mm/s, where the STEPPER DRIVE is 34-36 dB, and the SERVO DRIVE is only 32dB. The STEPPER DRIVE is 40 dB above 300 mm/s, which is 6 times faster than X-MOTOR's max speed. And the SERVO DRIVE is 40 dB at about 800mm/s, 16 times faster than max speed of X-MOTOR and 2 times faster than max speed of the STEPPER DRIVE.
So, comparing "apples to apples" - the SERVO DRIVE is the quietest one.