Exactly. I'm using
this thing and in combination with the DIR-615 I can often get 11.5MB/s when doing LAN transfers which translates to a respectable 92Mbps. I believe even this modest 2.4GHz 1x1 MIMO Mini PCI could manage more but of course it's being limited by the non-GbE ports of the DIR-615.
(Wait... maybe that should be 1x1 SISO. I always assumed wireless N was MIMO even with only one antenna each for Tx/Rx)