Heyyo,
Well, maybe it's your system specs dude. I have no problem with map changes at all. I get plenty fast map transitions, and the bot rarely lags down if any lag at all.
I've got:
AMD Athlon XP 1900+
512 PC2700
Sapphire's ATI Radeon 9600 PRO (shitty card, many incopatibility issues, just get the ATI one.
)
Windows XP Pro