While this indicates the possibility of specific hardware incompatibility, this problem has been shared by both MacBook and MacBook Pro owners. For instance, when plugged into A/C power, servers can be pinged with a consistent response time however, when switching over to battery the response time will become very erratic. It appears this problem for the most part happens when people run on the battery, as described in several Apple discussion threads ( 1, 2). Despite these, many other people who have updated (including us at MacFixIt) have not had these WiFi problems even on the same hardware reported. There are a variety of reports regarding this issue, some of which claim the WiFi cannot connect at all, others that claim WiFi is slower, and some discussing only intermittent WiFi connectivity.
Yesterday we found that some laptop owners who applied the 10.5.8 system update were having difficulties connecting to their WiFi networks.
