Hi,

Below are mentioned the key differences

1.One difference as you said is Sup720 can forward up to 400 Mpps whereas Sup32 at 15Mpps

This is huge difference in terms of throughput

So when complete 6500 chassis is filled with Rj-45 modules , and all ports are heavily utilized , Sup720's 400 Mpps will give better results than Sup32's 15 Mpps

2.Other key difference is Distributed Cisco Experss Forwarding (DCEF)is possible in Sup720, but it is not in Sup32.DCEF gives capability to line cards or modules to populate the forwarding table with local copy on the module & make forwarding decisions on module itself locally , providing maximum performance & scalability

HTH...rate if helpful..

The biggest difference between the two cards is the sup720 provides a 720 Gbps switch fabric. (Prior to the sup32/sup720, there were separate switch fabric cards that could be used with the sup2.)

The sup32 only supports classic bus line cards. The sup720 supports classic bus line cards and both (old) CEF256 and (new) CEF720 fabric line cards.

The other difference is the sup720 supports either a 15 Mpps forwarding rate for classic bus cards, or up to 30 Mpps for fabric line cards. Also with the latter, some fabric line cards support distributed forwarding on the line card if a DFC is installed. Distributed forwarding performance varies on line cards between dCEF256 and dCEF720 (which I recall[?] as being, on the line card, 15 Mpps for the former and 48 Mpps for the latter).

Performance shouldn't be a real issue between line card and supervisor for either sup32 or sup720. More likely issues are data forwarding bandwidth and forwarding performance.

For classic bus line cards, the whole chassis shares the bandwidth (in concept, somewhat like an Ethernet hub where line cards are the "ports"). For fabric line cards, line cards might connect to 1 or 2 8 Gbps or 1 or 2 20 Gbps fabric connections (in concept somewhat like an Etherner switch where line cards are the "ports").

15 Mpps provides about 10 Gbps forwarding for 64 byte sized packets.