3DMark & PCMark Vantage
The 3DMark Vantage results reflect the balance of power: AMD’s Hybrid CrossFire mode provides the best performance, followed by the combination of shared memory and side-port memory. The single Radeon HD 3450 and side-port memory on its own perform poorly.
PCMark Vantage also shows that side-port memory alone isn’t a good idea. However, the combination with shared memory again appears to be a good choice.