You might want to query sysconfigures and syscurconfigs to get information organized the way you want. For example, sp_configure without any arguments lists the memory used for configuration parameters, but it does not list minimum and maximum values. You can query these system tables to get a complete list of current memory usage, as well as minimum, maximum, and default values, with the following query:
select b.name, memory_used, minimum_value, maximum_value, defvalue from master.dbo.sysconfigures b, master.dbo.syscurconfigs c where b.config *= c.config and parent != 19 and b.config > 100
