There are some options that are very useful while working with the Lookup Transform; using them will help use the Lookup Transform to its full potential with improved performance in most situations. The next two options reveal these advanced properties.
As Lookup Transform looks for every record from source input inside the reference table, there should be performance tweaks to use during this lookup. SSIS provides a way to use the Cache option and cache the lookup table.
There are three options in the General tab of the Lookup Transform Editor's Cache mode setting: