[E6300]

It's because the 7-Zip file manager first extracts to %temp% and then copies (not moves) to the drop location. If you use the regular extract function it extracts to the destination directly. Using the Explorer context menu does the same thing, and thus is also fast.

[kyteland]

I use the right click context menu on the archive file to 'Extract Here' which seems to accomplish the same thing.