Am I correct in thinking that the WAN port for the cable modem on the 2850 is only 80 Mbs and they have now made this on the 2860 to Gigabit WAN. The reson I say this is I have a 120Mbs with Virgin but when I run through the 2850 I can on get download speeds of arround 78Mbs? Just checking I have not got some setting wrong. Thanks for your help Tony.

The Lans are Giga so & the Lan 4 which is the incoming wan 2 but its firewall has throughput 90mb & also the set up at 3) plays role for the wan 2

When i was in UK with VM 100mb at the end managed to get (that time being) the 105mb

1)
First ... from my own testings i think the modem codes STD and UK_SEG(232201) seems are little better for wan 2 ... from around same speed as you (70-75) ... got 5-10 mb more after changing the modem code to the ones i suggested .... and set WAN >> Internet Access>>wan 2>>Mode always on & MTU 1500 (1442 by default) because cable connection usually is 1500 ...
worth to try first the steps above

2)
However the big difference was when i disable the wan 1 (is on by default) ... i have test this option with 2 models (2830 & 2850) successfully

Thereafter it did managed to get from 80-85 (had it fine tuned) ... 105mb in most time of the day ( i suspect and local congestion was affecting easy the draytek so sometimes was still lower) but yea seems if both wans are enable ... seems it slows down the CPU

When just i moved house and gave them back their SH 2 that i was testing ... after a week the speed gone up to 120 so never tried if my 2830 & 2850 can do it ... but i am sure if wan 1 is disable ... (WAN >> General Setup>>Wan 1>>Enable: NO) ... it should reach very close at least if not all

3)
You will also need (if you have not) to get a giga Lan card port for your pc/laptop as well to get the extra benefit of the speed ... it will help maybe by up to 10mb more
As mentioned the 2850 has Gigabit Lan ports but if "understand" the pc/laptop (at these high speeds) is 10/100 it will automatic will give 10/100 access .... in this case go to WAN >> General Setup>>Wan 2>>Physical type try 100mb dublex ... but if you have not at pc 10/100/1000 may not help

Please let me know what speeds can get with the wan 1 disable ... Thanks