Product and Software: This article applies to all 802.11n APs and ArubaOS that support 802.11n.
A single spatial-stream client can get only 150 Mb/s with 40 MHz channel usage. If a 20 MHz single spatial-stream client is used, the max is only 65 Mb/s.
It is not recommended to use 40 MHz for 2.4 GHz enterprise environment. The same would explain why an iPhone 4 cannot reach 150 Mb/s even when it is used with 802.11n APs.