Hi,

i've just got couple deco M4, after everything have setup done, i do speed test on my iphone 6s and always have upload speed just slower than my download speed, some time just half via speedtest. 
My setup is used ethernet cable connect these devices ISP ROUTER(192.168.1.1) --> main node M4 (router mode: WAN 192.168.1.2 and LAN192.168.0.1) --> gigabit switch--> slave M4 node (192.168.0.4).

my ISP band with ~ 100Mbps
 

1. computer gigabit lan port connect to switch (have ip 192.168.0.xx) have download/upload is 95/95mbps. Wifi from computer show download/upload 95/60 Mbps
2. all ios devices (ip6/6S/Xmax) whenever in 2.4Ghz or 5ghz always have download/upload around 95/(40-50-60) Mbps. Same speed for main node and slave node with these devices. 

 I even test the same number 2 with only one node (router mode) connect by ethernet to ISP router and have identical result as upload always slower than download. 
3. turnback to previos very old wifi router i got same speed for download/upload. 
4. wifi of ISP router showed same speed for download/upload (this function normally is off to reduce the intermittent of signal)

options setting:
a. There is no setting in QoS and high priority.

b. all tests above did with fast roaming on/off and beamperforming on/off which have same result as mention above

c. All device tested in closely position of deco M4

pls help to figure out. Thanks