John,
From Cisco : http://www.cisco.com/warp/public/cc/pd/ifaa/ifpz/ggethifpz/prodlit/geip_qa.htm
Q. What is the difference between the GEIP+ and GEIP?
A. The GEIP provides moderate performance capabilities, appropriate for WAN Edge uplink applications supporting nxT1/E1 to a few DS-3s. The GEIP+ significantly extends Gigabit Ethernet performance on the Cisco 7500 series router. The GEIP+ provides high-performance solutions for Gigabit uplinks from the enterprise edge and data center, as well as in service provider points of presence.
