Sean,

Params = field values, it is always  link_la_typ.lat_typ_id and link_la_typ.lat_ga_id i search, but always with diferent params.

OS is Win7 x64 - its my development  machine.
I plan to put database on win2008 R2 x64 server wit 20GB RAM.
I dont know what is depth of an index.Index is created as
CREATE INDEX _LINK_LA_TYP_IDX5 ON LINK_LA_TYP (LAT_GA_ID, LAT_TYP_ID);

I hope this helps.

Zoran