>AFAIK, the reason for the poor memory performance of Cyrus/X5000 (clearly contradicting the specs of the memory controller) has not been determined yet. We just know it's not the OS as it's equally poor on Linux, OS4 and MorphOS. This leaves the SoC (memory controller), the board design or the U-Boot firmware as contemplable culprits.

Hopefully its a configuration or firmware issue that can be rectified in the future.
Obviously it can't be the memory, which is the same sort of DDR3 used in other machines.

If this is something that can be addressed, then its a little early to start throwing up red flags about it.
And we knew about the PCI-E limitations quite awhile ago.