Bought the Archer MR400 to use as a 4G failover for my M9 mesh network. 

After a lot of testing incl another thread, I've discovered the wireless speeds seem to peak at 75Mbps, not the 300Mbps that tplink tout.

Just to confirm previous config: Virgin router going into > Deco M9 (x3). 2m away from primary Deco with direct LoS & get 200Mbps using fast.com and okla speedtest sites.

Regularly, all the time. 

So swap config to Virgin router -> Archer MR400, same situ, peaks at 75Mbps.

Before its mentioned, I'm a principal RF engineer in telecomms and know a thing or two about RF propagation, interference etc etc... 

Needless to say I've done my best on that front.... the SNR or C/I is clearly good enough to support better than 75.

End of day, we have 2 products, with the Archer no where near the spec it suggests - so any ideas anyone? Anyone found the same?

tplink anything to comment / suggest?

The idea is to have my 200mbps as usual and failover to my 4G when cable fails.

Sure, the system work, I get failover from 75Mbps to 30Mbps 4G - but thats not good enough.