If you meant two 4GB sticks in dual channel, for a total of 8GB, vs a single 8GB stick, then yes, 2x4GB gives you slightly more performance than a single 8GB stick.
If on the other hand, you meant 8GB vs 16GB (8+8), then other than for the dual channel mode, you won't get any significant benefit from 16GB's of RAM, unless you run multiple VM's or something like that. For normal home power users, 8GB is more than plenty.