Used to regularly run 200 region of players tournaments with powerful PC. No slowdown issues whatsoever. think a couple of times during one time period it would crash once during a tournament but we just restarted the application i believe.
We just used TD to register, initial seating draw then for displaying blinds, breaks, prizemoney and a current player count and table count, we balanced tables manually using seat cards which is very effective for MTTs with probably around 1 floor person for every 5-10 tables (Your seat cards told you what was empty, how many players you had left as the players handed in the seat cards for empty chairs as they busted and then ket you informed of short handed tables and when you could break tables down). Once we were down to the money we gathered the remaining players names, and busted everyone out and re-entered the remaining players names and busted out in the correct order from there on in and did a final table seating draw using the software.
Theres so many different ways you can use the software though. If you have enough staff on the floor the names can be eliminated in the correct order for example. Simple mode allows the screen to be kept upto date without names being ran through. The way we did it worked well though as when you get down to the bubble you have a lot more floor staff to keep on top of names.
UHF radios really help those sizes of tournaments, someone can be at the terminal full time updating the tournament in real time. My way allowed regular updates to player/table counts by counting the spare seat cards. Its more about the floor staffing level than the software in my experience, most software out there can handle 500 players no problem, but that size of tournament is no good on any software unless you have the staff to keep upto date.