Netscaler Knowledgebase

No, although I can anticipate that it is at least a 30% hit on the cpu as the buffering impact will be similar to tcpb, which generally is about 30%.  That hit though is only for the objects that are really being rewritten, if you write your rules properly, only the html pages will cause the overhead, not images, etc, so the actual impact will be smaller than 30%.

The Oracle