A camshaft phaser includes an input member and an output member defining an advance chamber and a retard chamber; a valve spool moveable along an axis between an advance position and a retard position and having a valve spool bore with a phasing volume and a venting volume defined therein such that the phasing volume is fluidly segregated from the venting volume, the valve spool having a first spool supply passage and a second spool supply passage which is diametrically opposed to the first spool recirculation passage. The first spool supply passage and the second spool supply passage each provide a path for pressurized oil to be supplied to the phasing volume from an oil source.