no issues that i know about, but try posting in a forum devoted to Intel MSI boards
also, don't just get "any" 2.4b, get it from <A HREF="http://phamcomputer.safeshopper.com/73/572.htm" target="_new">http://phamcomputer.safeshopper.com/73/572.htm</A> if you're smart. you take your chances with fry's outpost, i got an SL6RZ malay Q chip from the tray there, and they SUCK. pham guarantees costa rica, which is the good stuff. SL6EF are also good chips. and any SL6RZ L chip, not Q, does decently (though not as well as a 3 chip, which signifies Costa Rica)
oh, and how well do they do with aircooling? 3Ghz at stock voltage guaranteed, and they generally get to 3.2-3.6 overall
well it seems you've gotten lucky with a few batches of 2.4Bs, that's why i say that =)
i don't personally know of any specifics about one plant being better than another, just that some batches out-perform others.
here's your link: <A HREF="http://forum.oc-forums.com/vb/showthread.php?s=&threadi..." target="_new">http://forum.oc-forums.com/vb/showthread.php?s=&threadi...;/A>
be warned: the thread is now 44 pages long. basically the summary is that costa rica SL6EF, SL6RZ, and SL6S2 (2.53ghz) chips are doing really well. chips from the malaysian plant that have "L" at the front of their FPO/Batch# also do really well. It's the Q chips you gotta stay away from.
As i said though, i don't really have an opinion on the plant, just that recently it has produced very overclockable chips