@mirosh82 
 i also have just got an S4 (and same firmware as you), my laptop connect via a switches to the s4,
 I was using the old cat 5 cable that i've used forever, but i noticed that would auto-negotiate to 100M and sometimes to 1G, 
 i could determine this by decoding the lights on the switch.
 I swapped the cable to a cat 5E and now i get a more consistent 1G. (negotiated cable speed, but my throughput is still limited by ISP).

 you could try: another shorter? cable, a cat-6 cable?
see if cable is near power/electrical lines/interference?,

good luck, hope this helps
GT



  
 
 

  @gtb Thank you!  I ordered a shorter, better Cat-6 cable...let's see if that does the trick!  I am not totally convinced, just because I can use my current Cat 5e cable between my modem and PC directly, and I get 800Mbps with the same cable.

What is the Light combination that you can look at to determine the link speed?  Or how can I determine what my link speed between the Deco & the modem is being negotiated at?

Thanks for your reply!

Mike

  @mirosh82 

my set up is:   modem <-> s4 <-> switch-8 <-> switch-4 <-> dockingstation/laptop
                                                      ^                      \
                                           other s4s, tv, etc...        \> nas, etc.


I periodically just run dsl speed test on the laptop, this gives me end-to-end throughput.  when i see it below 100mbs,


  i turn around and look at switch-4, and i can see the leds...
  it's a netgear switch, and each port has 2 leds,   right = 10mbs, left = 100mbs; both = 1gbs/1000mbs
 

alternately in windows i would look at settings/network and the ethernet properties and link speed is shown there.

the inter-switch connection i checked when connecting the first time, and it never gives me trouble.
 

my s4s haven't really given me problems on the ethernet ports,
 

so i don't see a way to directly read the link-speed from the s4 itself.
  that may be a good follow-up feature request.   (the internet connection tab on the deco app should show the negotiated link speed for the ethernet connections)
   for the WAN connection's link speed and

    link speed for the other ethernet ports ( for the back haul and hardwired clients)

from the deco app, in the deco lab there is a wifi assistant that has a speed test that can test  cell >> S4 <-> modem...
  I can see over 100mbs on mine, my cell is not "fast", but fast enough to independently confirm the S4 to modem link is faster than 100mbs.

I've logged into the modem and the only info i see is the cable side of things, 

When my troublesome link is o.k. (2 green lights on the switch) then my end-to-end throughput is > 100mbs.  
in this "good" state, i infer the 4 ethernet hops are 1gbs,  and my throughput is capped by the modem  (currently i'm provisioned at 400mbs, but it varies from 250mbs - ~400mbs

i hope you track things down,  but yes, it could be either cable in your scenario.

best of luck.

gt

  @mirosh82 Do you have any devices specified as "High Priority"? I thought I had a similar issue but it turns out, I think, that my device was being capped due to other devices being specified as "High Priority".