Can you share the chipset, wireless client driver version etc? Could you please enable BCMC on VAP profile and also on VLAN to re-test again to see how it goes. What happens if we have a on more client connected direclty to the controlller and do the iperf test between wired devices connected directly to controller, then connect the same client on uplink switch same VLAN wired and again do the test. By this way, we get throughput on wired devices, wired to wireless , uplink switch wired to compare the results.
(sri-7240-xm) #configure terminal wlan virtual-ap default
(sri-7240-xm) (Virtual AP profile "default") #broadcast-filter all
Warning: broadcast-filter arp should be enabled with this option. Otherwise ARP requests will be dropped!
(sri-7240-xm) (Virtual AP profile "default") #broadcast-filter arp
(sri-7240-xm) (Virtual AP profile "default") #
(sri-7240-xm) #configure terminal
Enter Configuration commands, one per line. End with CNTL/Z
(sri-7240-xm) (config) #interface vlan 10
(sri-7240-xm) (config-subif)#bcmc-optimization
Thank you,
Sriram