Decrease loading-times of gmod

I first installed garry’s mod with Counterstrike:Source. The time to load was about the normal.

Now that I installed the orange box, it takes about 10 minutes to play gmod.
I guess that’s because of the more content it has to load; can I somehow disable content that I’m not using, without removing all the Half-Life2: EP1/2, Portal, TeamFortress content completely?

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menu -> extensions.