Help to create indexes to improve query performance and reduce report generation time
As you are running a lot of (MEM_Name IS NOT NULL) against the memory table I would look to create a filtered index on this table to begin with.

CREATE NONCLUSTERED INDEX Memory_MEM_Name
ON MEMORY (Index Fields here)
WHERE MEM_Name IS NOT NULL


in most occations every table should have a least 1 Index.

You should capture a work load trace via Profiler and then run it through the database tuning advisor this will tell you where you should see gains with indexs (and even create them for you)

http://msdn.microsoft.com/en-us/library/ms181091.aspx

When running the DTA it might be a good idea to run it against a test system if you have one rather than an online system. Make the changes it sugests and then run it again to see if the improvements appear.

Note - I would not have called a table master. Master should be reserverd for the important master database.