> What's "wrong" on the MacMini?

While I don't have an answer to that question I just want to add that it's not only the Mac mini showing such low figures compared to the Sam460ex:

------------------------------
Powermac G4 Gigabit (7455 1GHz)
[...]
VIDEO BUS
READ: 38 MB/Sec
WRITE: 126 MB/Sec
------------------------------
http://amigaworld.net/modules/newbb/viewtopic.php?topic_id=32673&forum=33#588009

------------------------------
PowerBook 1.67GHz
[...]
--- VIDEO BUS ---
READ: 32 MB/Sec
WRITE: 159 MB/Sec
------------------------------
http://amigaworld.net/modules/newbb/viewtopic.php?topic_id=32673&forum=33&start=40#588294


Pegasos II G4 seems to be placed between G4 Macs and Sam460ex:

------------------------------
Pegasos II 1GHz
[...]
--- VIDEO BUS ---
READ: 52 MB/Sec
WRITE: 220 MB/Sec
------------------------------
http://amigaworld.net/modules/newbb/viewtopic.php?topic_id=32673&forum=33&start=40#588294


For me it's not clear whether the Sam460ex results are derived from PCI (onboard GPU or Radeon in PCI slot) or from PCIe.