Since this whole CPU issue seems to be blowing up, I decided to follow up on where my friend got the original information, which is from this MacNN thread. While he swears that this isn’t a reporting error, but a noticeable speed difference, an email exchange led me to try to double-check Xbench CPU scores. It appears, at least in my case, that there’s no difference pre or post PMU reset. Also, some people have mentioned this is only happening w/ 12″ AlBooks, but I do have at least one report of a 1GHz TiBook being affected. So, real problem? Reporting error? I’ll keep an eye out, but my own tests seem to point to the former, but your experience might be different.
Update: second report of the 867MHz being significantly faster than the 533MHz