I have been on ADSL2+ for about 1 month now and up to yesterday the download sync speed has been rock steady albeit slightly worse than previously.
It's probably worse because the Min SNR now seems to be set at 12 Db compared to 9Db before.
Last night, however, my download sync speed dropped to 5651kbps and I received a message "Bandwidth Usage Reset" and my IP Profile is now reduced to 4500kbps from 5500kbps. I'm stuck with this for a few days now.
Is the stability of ADSL2+ (21CN) worse than the old system?
The only real value of ADSL2+ for people with attenuation's greater than 40Db is the much improved upload speeds. For download speeds it seems to exaggerate the Post Code lottery.
Statistics today:-
Mode: ADSL2+
Channel: Fast
Trellis: U:ON /D:ON
Line Status: No Defect
Training Status: Showtime
Down Up
SNR (dB): 12.1 6.8
Attn(dB): 43.5 21.3
Pwr(dBm): 0.0 13.0
Max(Kbps): 7740 1160
Rate (Kbps): 6259 1123