In the days when memory was expensive and limited the best way to get ILM to perform was to get really fast storage.
Now we have servers with incredible amounts of memory (at least I do lately, yee-haw!) so getting a huge performance boost can be as easy as enabling PAE in Windows, and AWE in SQL.
This only pertains to ILM, since it runs only on x86 and needs these things to use all that memory. In FIM we get this for free since it only runs on x64.