running a router on a stick? yeah, that will do it. check the interfaces for output drops.
if you are getting them, time to look into a L3 switch to offload the inter vlan routing.
I have a 3750E 24 port gig switch with 2 10gb ports.
It absolutely rockets data through it at full line speed. MY 1921 however tends to vomit a little at about 60-75MB/s max line speeds when intervlan routing which is still quite high for a router in this class if you ask me.
I have to loan to a customer of mine in a pinch and am going to be converting my home network to my 8 port ehwic for a little while in the back of my 1921 isr. I didnt want to overstress my routing processor too hard but being that you really cant overheat them I am not worried for the two weeks I will be loaning my switch in a pinch.
I do not like routing on a stick when I have such a good layer 3 switch to do intervlan for me. This is completely temporary.