It depends. Sometimes the motherboard circuitry has enough
capacitance (accidental or deliberate) to allow the clock
to continue and the CMOS RAM to retain its settings for a
short period - some people have reported days, but that's
unlikely - even when the battery is removed.

-----Original Message-----
But doesn't the BIOS retain the data for half a minute or
so, when the
battery is removed? (Not sure, just wondering).