Well, I am the "one other person" in Bekar's original post, and I can assure you that it's none of that. At least in my case, the CPU spike coincides with mIRC's notify check, which automatically happens every 30 seconds; I also get a spike when I type "/notify" (without parameters) forcing mIRC to update the notify list. And yes, this is with remote off..
The nicklist colouring entries I have all refer to userlevel entries; I suspect that updating the notify list somehow causes a loop to check all wildcard userlist entries against all nicknames on all channels I'm on, explaining the CPU spike. I've turned off nicklist colouring permanently as a result of this.
