When it comes to evaluating the work load of a router running OSPF, what is more important than the number of routes are the route types (intra-area, inter-area, external), the number of routers in the area and the stability of the links in this specific area. That being said, I assume if you only have a 100 routes that the area is quite small and that the 3750 should be more than capable of handling the job.
Hope this helps,
Harold Ritter
Sr Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
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