My Microsoft MN 720 WiFi card had ridiculous ping times to my 802.11g base station - in the order of 50-120ms. This dropped to 8ms when I turned the "Power Save Mode" to "disable" or "fast" in the Windows Device Manager.
Theoretical speed didn't go up much, but it feels much faster - especially LAN stuff.
Note: This and most/all other early Microsoft WiFi gear were based on Broadcom chips, and this drivers still work even for Win7 and Win10.
Update: This card is still being used by me for a pseudo-HTPC. There are hacks out there to use WPA2 with this card. The Microsoft drivers will not work. You can force-install some Dell drivers. I've used them, it works. I've also had to limit the speed of this card to 36Mbps from 54Mbps, it just flakes out at top speed for some reason.
tags: wpa2, wireless, wifi,