Still same question, why would upload sync speed be reduced when download has remained the same?
Because they use different chipsets, and its been shown before that different manufacturers of ADSL chipsets cause different effects on the same line. Also goes with the chipset in the exchange DSLAM as well.
My BE line works well using my TG585v7 and I'm getting today 18mbps download sync, with 1.3mbps upload - and I get uptime measured in 10s of days.
If I use my Draytek 2820Vn, then I sometimes see 20mbps download, but 800kbps upload, and its very unstable, and disconnects several times a day.
The TG585v7 uses a Broadcom chip. the Draytek I believe is using Infineon.
pro - on THFB - sync about 17.2mbps - BQM