See 'WikiDevi' @ the Internet Archive (MW XML, Files, Images)
upgraded MW to 1.30 - maybe things are slightly less broken
TurboQAM is the Broadcom name for non-standard 256-QAM support on 2.4GHz 802.11n enabling a data rate of up to 200Mbps per spatial stream instead of 150Mbps with the standard 64-QAM.
Maximum Data Rate per spatial stream @ 40MHz for 802.11n and 80MHz for 802.11ac:
|802.11n||150Mbps (64-QAM)||200Mbps (256-QAM)||250Mbps (1024-QAM)|
|802.11ac||433Mbps (256-QAM)||N/A||~540Mbps (1024-QAM)|