The fabric capacity for the 4500 is documented with the 4500 supervisor specs.
The chassis provides either 6 Gbps (original 4500s) or 24 Gbps (E series [and with E series line cards and sup]) bandwidth to the line card.
Generally, most of the 4500s sups fabric bandwidth supports the full bandwidth to the card slot (recall some exception with the 4510?).
What is it you're trying to understand?
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BTW, line card specs often document how they use the bandwidth to the card slots. For those cards with more port bandwidth than the slot supports, might be something like every group of 4 gig ports share 1 gig of the card slot's bandwidth. As least one card provides full bandwidth to a couple of gig ports and shared bandwidth to the others.