Bob is right. An IG for computer stuff should land on the same bus as the main bonding jumper and ground electrode conductor. You want a "star" originating at the MBJ/GEC junction. Grounding should then branch from there in a tree structure so there is no parallel path.
Back in the day we never brought a neutral to a computer room panel (all L/L loads) and we used the isolated neutral bus for the IG. Equipment and raceway grounding was on the bonded supplimental bus.
(In a prior life I was an IPR for IBM designing computer rooms).
