Hello Dan,
an advice:
performance of GEIP+ are far lower then declared consider them as a way to provide a GE port to the device.
With small packets capabilities for us were in the order of less then 100 Mbps
With big packets we could achieve up to 260-280 Mbps.
A c7505 should have a single Cybus running at 1Gbps : a shared bus for all linecards/VIPs
All packets are actually moved via MEMD that is on the RSP (for the legacy cards) so the platform is not really distributed.
If you look for performance it is better to look at othe platforms:
a C7200 with NPE-G1 or NPE-G2 behaves better just to say.
C7500 has been a very good router, but now its performances are too low for most applications.
Hope to help
Giuseppe