The 802.11n wireless LAN does not achieve full line rate performance - ThinkPad
The 802.11n Wireless LAN Mini-PCI Express Adapter, when connected to an 802.11n wireless LAN Access Point (AP), does not achieve full line rate performance (limited up to 54Mbps).
Any systems with an 802.11n Wireless LAN Mini-PCI Express Adapter may be affected by this symptom.
To connect the 802.11n wireless LAN AP with full line rate performance:
Configure your system to Advanced Encryption Standard (AES) encryption using Access Connections (or other wireless utilities). AES is supported by all secure authentication schemes such as WPA/WPA2.
Make sure your 802.11n AP is configured to AES encryption for 11n mode. Check with your 802.11n AP manufacturer for specific instructions on how to configure AES-based security.
If you are connecting with the IEEE 802.11a/b/g or IEEE 802.11b/g AP, then you can disregard these instructions and keep your current security configuration.
If the 802.11n AP and a system with an 802.11n Wireless LAN Mini-PCI Express Adapter are configured to data encryption other than AES, your data rate will automatically downgrade to the legacy IEEE 802.11a, b, and g since other encryption types are disallowed by the IEEE 802.11n standard. To maximize the performance benefit of 802.11n, the AP and system must be configured to AES encryption. All commercially available 802.11n products support AES encryption, as this is a required by the standards bodies governing the wireless LAN industry (IEEE and Wi-Fi Alliance). 802.11n wireless is based on IEEE 802.11n. The IEEE 802.11n specification has not been finalized and is currently in draft release.