Changing my username realm helps, but my line isn't operating normally, it's everything, not just downloading.
Speed test shows normal now:
http://www.speedtest.net/result/2213764176.png, but real world tests show otherwise.
Browsing is sluggish, but not every time, now and again a page is taking a lot longer to load.
Downloading is extremely erratic, spikes up to around 400Kb/s, but the average is around 150Kb/s. I tested a local download from tenet mirror, it was consistent but only reached 300Kb/s, full line speed for me normally is 450Kb/s.
Note the above comments are since changing username realm. Before changing username realm, everything is slow, nothing (streaming, browsing, downloading) exceeded 120Kb/s.
I logged a fault with Telkom, not sure what they'll do/say.
I hope this isn't a sign of things to come with the 1Mb upgrades...