The G1379A degasser cycles between ON and OFF stages for degassing (as does the G1322A degasser, but the G1322A has a much higher volume which helps mitigate these effects). The G1379B degasser ramps the vacuum pump when needed but is always running at least 20% power.
The G1379A degasser can be converted to "Constant On" mode so the vacuum pump runs 100% of the time, but may decrease vacuum pump lifetime and is only advised if baseline fluctuations are seen that coincide with degasser On-Off cycles. This is accomplished by switching the DIP switch 1 inside the degasser to the ON position (UP when it is normally both switches are DOWN).
This change and vacuum pumps/degassers may not be covered by your Agilent hardware service contract depending on what analysis conditions warranted the change to "Constant On" mode.