I tried it in my 2860. All kinds of wifi problems with every kind of device.

I've gone back to 3.7.4.5 from December last year. No problems now.

I've recently upgraded the firmware on my 2760 from 3.7.8 to the current 3.7.8.2 which include G.INP and vectoring support. Whilst my ping times have dropped, the DS SNR has gone from 5dB to 9dB and the maximum attainable DS is now 45,800 which is a pretty fair drop from some 57800kps. Whilst it seemed unstable at first, it now appears OK

I get the impression that G.INP and vectoring are really designed for Broadcom chips rather than those that Draytek use - Connexant or whatever they're called nowadays.

I'll give it a few more days, but does the 'factory' reset also reset the firmware and modem code to their original states, since it looks likely that I'll be reverting to 3.7.8

Just to confirm that the draytek.co.uk supplied 3.7.8.2 with the 574307_571801 modem code also works fine on TalkTalk FTTC 73999/19999 sync; HW acceleration off though.
/Rich