Hi @BITSNBYTES,

Is this a wareheouse?  Or similar one big room?  Or do you have separate offices?  How many simultaneous users are you expecting?

6 AP's in 4000 sq feet seems like a lot -- unless the space is broken up with concrete / plaster walls.  Due you have the transmit power turned down to medium or lower?  Are you alternating channels (honeycomb) and using a narrow BW e.g. 20MHz?

Are you using all Cat5e or better?  All runs less than 100meters?  Midspan injectors or PoE?  AP's are ceiling mounted, facing down?

Do you have separate SSID's for 2.4G and 5.8G?  Either should eaisly be able to do 50Mbit.  My EAP225V3 does about 350-450 Mbit'/sec DL & UP on 5.8G w/80MHz BW -- Upload is actually faster usually.  But depending on your country and building layout you may not have too many channels to work with unless you narrow your BW.

If you stand under each EAP, one at a time, and let you're phone roam to to the local AP (or turn the all off, and turn on one at a time), do each give the same slow speeds?

There have been the occassional report here on the board of EAP's that seem like they may have a bad antenna / amplifier here or there -- though we've never confirmed this -- but it is highly unlikely all 6 would be bad.

Seems more like an interference or cabling related issue.

Are you using Omada server or OC-200?

-Jonathan