Hi
If the setting is Not prescribed (like mentioned by chuck) it would
dependent on the Client's Drivers. Some of Wireless cards look first for
802.11g, many look for the strongest signal, and some can take Signal to
Noise Ratio (SNR) into consideration. If SNR is taking into consideration it
would go to the 802.11a since the 5GHz band is much cleaner than the 2.5GHz
band.
Jack (MVP-Networking).