Further thoughts - it has been suggested that changing wifi channels may help. When setting up the HH5 last year I went through all the best channels using the wifi overview app and eventually realised the 'smart' auto channel hopping setting produced he most consistent results, the most contention I ever saw was 4 users on channel 1, but usually most of the 2.4Mhz channels show 1 or 2. The HH6 is also on smart and usually uses ch11.

But this obviously wouldn't affect the max data rate, as the main PC is wired to the hub via a 300mm ethernet cable and the router is connected via a 7m dedicated cable (genuine BT solid copper core, which alone gave a 1.5Mb speed improvement) hard wired into the ADSL faceplate.

HH5 stats show:-

up/down max line rate of 1108/17072

Data rate: 1112 / 16737
Noise margin: 6.7 / 5.4
Line attenuation: 13.5 / 28.1

HH6 stats show:-

up/down max line rate of 1284/16952

Data rate: 1.27 kbps / 15.12 kbps
Noise margin: 6.4 / 6.1
Line attenuation: 27

TIA - Alastair

Is your HH5 a Type A or a Type B ?

Both type A

So the different sync speeds could be because the HH5 has a Lantiq chipset and the HH6 has a Broadcom chipset