Different amounts of processing required. More processing requires more CPU which means fewer connections per second. Plus things that ca be accelerated don't use CPU so they get higher throughput (But tend to be simpler settings on the VS).
They're also measuring slightly different things. I think the L7 requests is requests over persistent connections (Little or no tcp 3 way handshake required). It doesn't define what sort though... L4 connections is TCP connections opened per second (3 way handshakes). While L4 HTTP requests is HTTP requests over persistent connections (Again little or no 3 way handshakes and obviously optimised so probably measuring FastHTTP profiles).
H
Nimbostratus
