[lucevans]

QAM64 /256 isn't a choice that can be reset by a modem reboot- it's the scheme of modulation that a particular network uses. Virgin Media is not one uniform network, but an amalgamation of many smaller local networks that have been created at different times, using different hardware by different companies. Gradually over the years, the number of independent local cable operators has diminished as smaller companies were bought-up by larger ones. The final stage of this process was when Telewest, NTL and blueyonder were consolidated under the re-branding called "Virgin Media Broadband" early last year.

QAM256 enables more bits per symbol to be transmitted, but is more sensitive to noise than QAM64, so requires better quality cabling and hardware in order to be reliable, hence some older parts of the ex-NTL network are currently not up to using it (e.g. Peterborough: ex-NTL > ex-ex-Bell Cable Media system is still utilizing QAM64 - and I don't have any particular problems with it, it works okay most of the time...)