I have a network with a DFL-200 and a DIR-636L connected to a 100/100 Mbit/s fibre network (ISP). Everything, including streaming movies and TV works flawlessly without so much as a hick-up - except YouTube. YouTube buffering can take several minutes even for a four minute clip. Even so, the clip will run for twenty seconds, freeze for a minute and then run for another twenty... Useless...
This occurs either connected to the DFL-200 with a cable or over WiFi - it doesn't matter.
When connecting a computer directly to the fiber cable modem, YouTube will buffer a 20 minute clip in seconds and the clip runs without any freezes.
There are four MacBook laptops, one iMac, one Mac Mini, an Apple TV and two iPhones on the network. All have the same YouTube issue.
Ideas, anyone?