OPi PC transfer speed via 300 mbps wireless N dongle

kris85

Hi.
I would ask You how fast should be transfer speed via wifi dongle which is conented via usb to OPi PC. I bought 300 mbps card, this card is set i AP (Access Point) mode. My laptop also support 300 mbs, in network conenction I see speed 300 mbps, but when I transfer files from OPi Pc to my laptop reached speed is maximum 9-10 MB/s (I mean Megabytes). I know that Wifi uses tx/rx so transfer speed should be 300 mbps/2 =150 mbps (150 mbps for TX, 150 mbps for RX), 150 mbps / 8 = 18,75 MB (Megabytes), I have only 9-10 MB. So maybe someone knows where is restriction -  maybe in usb controller ?  Opi pc (I think) has usb 2.0 controller which should be 480mbps. I would like to see at least 15 MB in file transfer. Maybe someone knows where is solution ? Does Opi pc 2 have faster usb ?
Regards, Kris.