I've searched but could not find a thread that addresses this (no flames). Both the Early 09' and Mid '09 share the same bus speed but the RAM speed is different 667MHz v 800MHz. I assume the Early '09 will accept the faster DDR2 800Mhz RAM from the Mid '09, but will it run at the faster speed? Is this a firmware issue as the Nvida Macmini (same bus speed) uses DDR3 @ 1067MHz? This seems like a bummer of bottleneck in the bus.