I'm getting about 2-2.7Mbps on my link test. The Question is how is this broken down, is the up down dynamic and adjusts accordingly or is it lock at 50-50 or some other ratio. Would my aggragate (both direction total) link through put be 4Mbps ?

I have same problem - Bandwitch test x86 2.9.8 x x86 2.9.8 show maximum 500 Kb/s, and I have usualy traffick on this link about 4 Mb/s and running on 36 Mb/s!
Between routerboard - routerboard is OK, but x86 x x86 not.