I've seen a post where the poster claims their PCBang edition tracks as well as the original (at 3+m/s max speed), but I can't verify. Asian market is pretty obscure, and the ones that I've got my hands on were no good.
Is the latest version of Synapse still worsening the performance of the Deathadder 3.5g?
I would hope it acted as a "pass-through" function at the native steps of 1800 an 3500 DPI. And that the processing at 900 DPI is fast enough to cause minimal problems, as it is basically a /2 divisor.