I'm transferring a video from a Synology DS 213j attached by ethernet cable to the router. I'm just dragging the video from the NAS to my desktop.
I'm going to try to transfer it to a laptop by wiring the laptop to the router. I guess I'll then bring the router/NAS system into my room to try to rule out wireless loss...but I don't think that's the case. My signal strength, as indicated by Windows, is only 2/5 bars now after moving the router upstairs and just down the hall from my desktop, with little affect on the transfer speed.
*edit*
Transferring from the NAS onto the SSD on my laptop via wired ethernet through the router only yielded about 41MB/s.