Multi-Domains plugin makes my site to be heavy.

After I installed Multi-Domains Plugin, My site was heavy.
( I use Domain Mapping Plugin.This is no probilem. )

For Example,

##Before I installed Multi-Domains
When I clicked " New Post ", It was shown after 1sec.

##After I installed Multi-Domains
When I clicked " New Post ", It was shown after 3sec.

In the near future, Is this issue resolved?
Can not do anything?