Hey guys
For what it's worth, I had similar problems with my "4Mbps" uncapped service from MWeb. So much so that I've more or less ditched the service in favour of Telkom LTE now.
I'm now about 2.5km west of the Faerie Glen (Petrick Avenue, +27-12-991-xxxx) exchange. At that distance, and with the poor quality of copper that Telkom has in the area, 4Mbps is really borderline. At 4Mbps the line is very unstable, with high attenuation and virtually no noise margin.
Apart from that, even when the line did sync at 4Mbps, it seemed that the congestion/backhaul issues were such that Telkom/MWeb could not deliver data consistently at anything like 4Mbps, as the graph below shows :
In March/April 2014 I was experiencing an average data throughput performance of around 1.5Mbps, even when the line was synced at 4Mbps. So this was a backhaul/congestion issue, not a line issue. I've also never used more than about 50GB in a month, which is way below any throttling thresholds.
After several weeks of whinging to Mweb, they managed to improve the service for about a month (see improvement in late April / early May in the graph above), but thereafter it started to deteriorate again - unstable at 4Mbps and about 20 disconnects a day. Not cool.
The other problem was that the maximum possible downlink sync speed (based on measured attenuation and SNR on existing copper lines) was never better than about 4.5Mbps. So without a line upgrade, I had effectively reached my xDSL ceiling at a paltry 4Mbps. Forget about ADSL2+ or VDSL - same problem. 10/20/40Mbps xDSL ? What a laugh.
Telkom aren't particularly interested in upgrading the copper lines in the area, and MWeb don't seem to care much either way, so it was a case of voting with my feet.
I solved the problem by moving to fixed-wireless LTE service. It's not uncapped, but now I can routinely get 25-40Mbps download speeds with no particular effort. I still have my ADSL line as a failover backup, but I've downgraded to a 2Mbps service, which works fine. There are many LTE-capable towers in this area on all 3 major cell networks (Vodacom, MTN, Telkom Mobile).
I gather that
Hemi300C might have done the same.
For anyone else suffering with cr*ppy ADSL performance, check out the
Huawei B593 LTE thread and the
Antenna installation and alignment thread for practical tips on how to make the switch.
Edit (Dec 2015) : I subsequently made the switch to optical fibre (Telkom line, WebAfrica as ISP) when FTTH became available in my block (May 2015).
Installation was eventually commissioned (after a very long wait) on 12 Aug 2015. Now on a 40Mbps service and very happy so far.
I still have my LTE setup but only use it as a failover for the FTTH line now. It has come in handy once or twice, although generally the FTTH is very stable and consistent.
