The latest Intel® Proset is version 16.6. If this still does not do it there are other possibilities to take a look at:
You may get more or less interference, depending on the wireless band used and your environment. If you have a crowded wireless activity near you it is best to use 5 GHz, otherwise use 2.4 GHz if walls or objects are an issue. Changing the channel within the band may also help when active interference is present.
It is always recommended to update the AP’s firmware.
The following article provides some guidelines such as channel bonding, security encryption, and others:
Thank you for your advice, which I shortly intend to follow-up upon.
I now realize I made a mistake in my original posting when I said that Intel had me update the driver to 16.0.0. It was actually 16.6.0.
I should also have added that the old computer with the Foxconn adapter is still operating at 300Mbps next to the new computer with the Intel Centrino 6205 operating at 72Mps. Also, curiously enough, the Foxconn does not have an external antenna, whereas of course the Intel Centrino 6205 does.
Thank you, joe_intel. I am making some progress due to one of your suggestions. By selecting the 5.2 GHz band, I have been able to increase the speed up to 120Mbps. I will investigate other configuration options at the next opportunity.