You can do a clean installation of the wireless driver for Intel® WiFi Link 5300. Download Intel PROSet/Wireless Software and Drivers for Windows* 7, version 16.7.0. Save the file to your computer.
If you have Windows 7* 32-bit:
Intel PROSet/Wireless WiFi Software (includes Drivers): Wireless_16.7.0_s32.exe
If you have Windows 7 64-bit:
Intel PROSet/Wireless WiFi Software (includes Drivers): Wireless_16.7.0_s64.exe
Go to Control Panel - Programs and Features and Uninstall the "Intel® PROSet Wireless/Software".
Go to Control Panel - Device Manager - Network Adapters, right click on the Intel® WiFi Link 5300 and select uninstall, make sure to mark the option "Delete the driver software for this device"
Install Intel PROSet/Wireless Software and Drivers 16.7.0 you had downloaded before.
Once the driver is updated, make sure to apply the settings from the following document:
Thank you for the quick response.
As suggested, I uninstalled Intel PROSet, deconfigured the device, and deleted the driver files. I downloaded Wireless_16.7.0_s32.exe and installed it.
This installed driver 18.104.22.168, which is the same level driver I upgraded to last Saturday. Then and now, I rather expected the driver to be level 16-something, but in both cases, the installation got me to version 22.214.171.124.
I made adapter changes according to the page called "What are the Recommended Settings for 802.11n Connectivity?" I changed the "802.11n channel width for band 2.4" to "Auto," and the rest were already on the recommended settings. I could make no changes to my router; its GUI doesn't support changing the options mentioned on the page.
With these changes, the Intel Wifi Link 5300 ran the dir /s test to completion in 39.53 minutes with inexplicable pauses in the output.
The USB wifi adapter finished the test in 8.88 minutes.