Delivery task: Keep instruction window full ? the deeper instruction look-ahead allows to find more instructions to issue to the execution units.
Fetch and decode instructions at a higher bandwidth than execute them.
The processor fetches and decodes today about 1.4 to twice as many instructions than it commits (because of mispredicted branch paths).
Typically the decode bandwidth is the same as the instruction fetch bandwidth.
Multiple instruction fetch and decode is supported by a fixed instruction length.