To get rid of fine dust (the stuff that actually matters) you need to move a lot of air. 800cfm plus at the tool.
The CFM ratings on dust collectors are usually grossly overrated and are free air tests.
Practically you need a 3hp dust collector. 6 inch pipe work to as close as possible to the tool. 4 inch to the dust collector will only move about 400cfm.
Removing fine dust is a volume game (large dust collector). Removing chips / large bits can be done with high velocity low flow (a vacuum).