I'm glad we've
finally discovered what the issue is: your line.
The problem now will be convincing Telkom to fix the issue. I reckon bad wiring is to blame (although your impeccable line statistics [besides the errors] would seem to indicate otherwise). If it is not the wiring, it *may* be the DSLAM port (?) - but this is speculation on my part; admittedly, I know nothing about DSLAMs and what-not (although I've read that there can be problems on DSLAMs too).
There are two things you can try. Phone them, and tell them that you are experiencing errors (and if they ask what kind, you can tell them CRC errors) that are affecting your line speed (but not synch speed). Perhaps they will know what to do then. If not, you can prompt them to either: rewire your apartment, or have a technician check out the DSLAM. I'm hoping others will chip in here regarding what to ask them to do. If not, you should start a new thread with your figures above and ask for advice.
Just for interest's sake, here's what the acronyms mean:
CRC: Cyclic Redundancy Check
LOS: Loss of Signal (I think this should show up as drop to 0 noise margin on the graphs - but you said there was no spikes/valleys?)
LOF: Loss of Frame
ES : Errored seconds (seconds out of the total uptime that have been affected by errors)
The high number of errors you have in a relatively short time period shows that something is very wrong with your line. These errors corrupt the data that your line is downloading. Therefore, as you are doing those speed tests, the errors are causing your line to have to re-download a lot of the data, which in turn is affecting your effective download speed.
It may be interesting to note if the raw amount of data coming into your PC/laptop is still at 450KB/sec (the speed you can expect on a DSL 4Mbps connection) but because the data is corrupt, only 172KB (1379/8) out of that 450KB is usable. You can do this with a program such as
Netmeter (assuming you are using Windows)
Here are my figures...
Downstream Rx
Noise Margin: 26.2 dB
Connection Rate: 4096 Kbps
Line Attenuation: 19.0 dB
Power: 8.3 dBm
SF: 18077540
SF Errors: 0
Reed Solomon: 0
RS Corrected: 0
RS Un-Corrected: 0
HEC: 0
Errored Seconds: 0
Severe ES: 0
Interleave Depth: 1
Upstream (Tx)
Noise Margin: 14.0 dB
Connection Rate: 512 Kbps
Line Attenuation: 12.0 dB
Power: 8.1 dBm
SF: 18078492
SF Errors: 0
Reed Solomon: 0
RS Corrected: 0
RS Un-Corrected: 0
HEC: 0
Errored Seconds: 0
Severe ES: 0
Interleave Depth: 1
Totals
Total Up Time:
1 days 13 hours 23 min 8 sec
CRC: 0
LOS: 0
LOF: 0
ES : 0
Bytes Transferred (ppp0):
Tx: 147052127 (140.2 MiB)
Rx: 1530286499 (1.4 GiB)
(yes, yes, I'm somewhat of a leecher
)