Usually Sonos doesn't pass enough traffic to be a real problem for your WiFi, really big systems playing multiple units at the same time can be an issue though.



Have you done throughput testing with the all Sonos powered on and off to confirm that it is the Sonos devices causing the issue?



Does it happen with the Sonos just powered on or only when playing music from one or both rooms?



Before buying anything I'd post a diagnostic to Sonos and the number either here or to the Sonos Twitter (24x7) or phones (when open) and let Sonos support see if they can find a problem that can be solved without costing you money.



Is there any way you can connect an Ethernet cable to any of your Sonos units? That will take them off your WiFi (and you should remove the WiFi SSID and password from the Sonos gear) amd put them on their own net. Just make sure Sonos and your home WiFi are on different (only use channels 1,6 and 11) channels.



Another alternative to a Boost that is nearly as good is adding another Sonos speaker in a location that can be Ethernet connected. That gets you another speaker, Boost connection mode and very little difference in the quality of the Sonos WiFi link.



Last choice would be a Boost, but only after working with Sonos support to make sure it would fix thkngs.

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