I found sitting on top of the router on a 5GHz 867Mhz connection from my USB 3.0 drive on the router about 45 MBs data troughput. On the 1Gbps LAN about 75 MBs. throughput.
Oh, Cat5e on a 14' connection was causing issues, could be my USB 3.0 drive and cable, I went to CAT 6a and all is well...
Not true, on N I can stream from the DLNA from the USB drive with no issue. The problem is you have to limit the devices. Once you get a lot of devices there even 300mbit gets choked quickly.
The problem here is you are only N 2.4 GHz. If you want to media stream you need to have at least a dual band router for wireless. Even so over LAN can still cause issues.
I am not sure what you want to stream but SD MP4's (up to 4mbps) I had no issue with my older Samsung NP60c6300sf, HD...