Seems odd, I just installed a cap lite in my lab environment so I thought I'd try this out. I setup iperf on a server in my LAN and ran iperf from my laptop connected to the cap lite.
TCP
[mikrotik@iperf1 ~]$ iperf -s -p 5201 -m
------------------------------------------------------------
Server listening on TCP port 5201
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[ 4] local 10.241.41.186 port 5201 connected with 10.211.11.32 port 2833
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-30.0 sec 201 MBytes 56.1 Mbits/sec
[ 4] MSS size 1460 bytes (MTU 1500 bytes, ethernet)
UDP
[mikrotik@iperf1 ~]$ iperf -s -p 5201 -u
------------------------------------------------------------
Server listening on UDP port 5201
Receiving 1470 byte datagrams
UDP buffer size: 208 KByte (default)
------------------------------------------------------------
[ 3] local 10.241.41.186 port 5201 connected with 10.211.11.32 port 55536
[ ID] Interval Transfer Bandwidth Jitter Lost/Total Datagrams
[ 3] 0.0-10.1 sec 113 MBytes 94.3 Mbits/sec 0.610 ms 2339/83022 (2.8%)
/interface wireless registration-table print
8 wlan1 YY:YY:YY:XX:XX:XX no -59dBm@HT40-6 180M... 13m7s
<laptop> ))) <cap lite> - ethernet - <cisco switch> - ethernet - <hex, intervlan routing> - ethernet - <cisco switch> - ethernet - <kvm host> - linux bridge - <iperf vm, single core, 1024mb of ram>
I didn't do anything fancy and it "just works." Additionally, it's one of the cheapest APs available.