In theory, 802.11n can zip by your 100Mbps Fast Ethernet at a real-world 160Mbps, but the practice it’s usually much slower. No, the Wi-FI vendors aren’t lying; the problem is that you have to set 802.11n up just right to really get fast performance.
First, you need to make sure that you’re using up-to-date 802.11n hardware. Older 802.11n equipment, built before the 802.11n standard was finalized in late 2009, may not work and play well with your newer devices. There were many 802.11n draft access points (APs), network interface cards (NICs) and chipsets and each vendor used its own best guess on what the standard would eventually look like.
Thanks to all this older, not quite standard 802.11n hardware, we have two problems. The first is that some older hardware, unless the firmware can be upgraded, won’t work at full 802.11n speeds with your newer standardized equipment. The other is that you can be almost certain that older APs, switches, or routers from one vendor won’t work well with another vendor’s equipment. Oh, it may look like it’s working, but if you check you’ll often find that your Wi-Fi’s connection is only running at 802.11g’s 54Mbps.