I've now tried the 3x3 mimo Atheros 9380 mini pci-e in bridge AP 802.11n mode with iphone, android and win7 clients with not that good result. I've more or less tried all channels, all different settings where clients could connect at 450mb but max tcp/udp stream seems to be around 20mbit. I do think that there is some missmatch with the FW on some cards and the driver in routeros, or that my card was not working ok. Running with 1*1 or 2*2 or 3*3 made no difference expect that the clients report that they are connected to that speed, but no difference in actual speed. The card was a http://www.ebay.com/itm/Atheros-AR5BXB1 ... 0524668862 card.

Did you try enabling the advanced rate selection? Please post your wireless config...

After about 15 hours of trying different settings I pulled the card, I was getting problems where no traffic would flow from ios or android devices once every minute and lasting about 15 seconds.

I tried to change more or less all settings, restarting rb800 and computers between settings tests. Legacy, advanced vmm, frequencies 2.4 and 5ghz. also differnt output powers. I have messed with ALL settings during this time. After each test I did a reset config too. To my conclution no setting would make it work better, just connect at a higher rate. Thus my conclution is either there is a missmatch with the driver and the card or the card was damaged. I could not tell the difference and I only have one card.

write to support@mikrotik.com and make the support output file at the time where you have connected your client and can't get the max speed.