Well in some cases it could be the client doesn't agree with the map. If you have a specific map that's timing people out you should check the clients values for mat_phong and r_rootlod.
https://forums.alliedmods.net/showpo...62&postcount=2
I have at least two maps on my server in specific areas where r_rootlod (model detail) must be set to 0 (high), and another map that crashes people with mat_phong 0.
Usually the people that crash end up being the ones with those crazy configs. Authurdead made a plugin for me that essentially dumps everyones cvars to their own file but I never tried it yet.
Maybe you could find some similar settings from the people that keep crashing on your server.