cef/process switching problem

I've got a cisco MC3810 with a bunch of DSL customers on it. CEF is enabled, but when I do a show int stat, I see that almost 100% of the outbound packets on the ethernet interface are process switched, and not being matched in the route cache. The Input looks just fine, and the other interfaces are borderline (usually 50% hit rate on the cache or a little less). CPU is sitting pretty high on this box during the day, and I have strong suspicions that this is why. :) I can't seem to find any info on why this would be happening or how to figure out what's going on. Anyone have any suggestions? -jay