I would copy a large file on your network with the 802.11b device (tivo) connected and time it. Then disconnect tivo, power cycle the router to reset it (some wrt54g firmware does not properly reset back to the higher 54mbps speed when the b device is disconnected unless it is reset). Then perform the same test copying the file across the wireless net. You'll find your speed is reduced to b-speed ~11mbps, despite what the driver tells you. It's an unfortunate limitation of the 802.11g protocol that the speed is slowed when a b device connects.