There are several reasons why a laptop or any wireless client is only getting a wireless link rate of 54Mbps from a wireless router such as the ESR350 even when getting full bars of signal. Below are a few things to check why a wireless client is limited to a wireless link rate of only 54Mbps:
1. Check if the laptop has an 802.11n wireless adapter. If the wireless adapter is only 802.11g then 54Mbps is the fastest possible wireless link rate.
2. Check the wireless security setting of the ESR350. iEEE 802.11n specifications require WPA2 (AES) encryption. Setting the wireless security to WEP or WPA-PSK(TKIP) will limit the wireless link rate to 54Mbps. Try setting the wireless security to WPA2-PSK(AES only).
3. Check if WMM is disabled. WMM is also an iEEE 802.11n requirement. Enable WMM to get 802.11n wireless link rates.