In game: depth 9; just entered out of the arcade from Moorcroft Manor.
Was fine until I entered the dungeon level- the client just completely bogged down-- the whole 3-5 second delay between commands and movement.
I turned the graphic quality all the way down, which seems to have helped it out- there's no more moving background, in addition to closing down all my other running programs (including a Terminal window-- the Java client was taking up 96 of my %CPU).
My system might just be outdated, however:
MacBook
Vers 10.6.4
1.83 GHz Intel Core 2 Duo
3 GB 667 MHz DDR2 SDRAM