Hi Roel,
Interesting behaviour!
I have the same experience. But I have the following devices:
Synology NAS, DS212+ -> 8 port, Gigabit switch TL-SG1008D -> KPN Experiabox -> Sweex switch -> Mede8er 600D
All cabled
When I play some video files (hi quality, DTS sound, etc) , it seems that the NFS connection is to slow and the datastream (HDMI) to my Yamaha amplifier and television is hikking up.

But.... with almost the same configuration, the KPN Experiabox is in my setup new, therefore I had an Tele2 modem/router all played very well and without hikking ups.
And if I change the NFS for a SMB connection the same movie plays without problems....

So I'm also facing a very slow NFS connection. But I'm not sure which device or settings is causing this problem.

Perhaps someone has the same experiences and a solution ?

Regards, MrRoubos

Hi Roel,
I resolved my own problem :)
The cause was in my mede8er box, the NFS-option of rsize was 'hard' set on 32xxx, when I changed it to auto and turn off and turn on the device. All works as it should be.
Regards, MrRoubos

Hello Roel,

How did you solve the problem? I have the same, but everything works if i use a normal switch in stead of the tplink switch

I have solved the problem!
I have changed the WDR4900 with another one in the shop, still it did not work! They gave me my money back, so I bougt an Asus RT-N66U! This Asus works perfect with NFS and also has a better range! Yes it is more expensive but it is worth it! No reboots for any change in the config, better range, NFS works great, much better building quality, much more options (like one click to configure is as an Access Point).
Sorry no more TP-link for me anymore.