It seems there is a nationwide slowdown affecting many Streamyx users.
However I have been receiving some reports that TM is implementing a cap of some sort that limits people’s downloads to 40 kB/sec or so if they are a heavy downloader. I am unable to confirm or disprove this but my gut feeling and from the support enquiries I have been receiving, I have not seen any indication of the sort.
A more plausible explanation is the repairs being done to the APCN2 link which should be in full swing now with an estimated completion date of 10 September. It has long been suspected that TM does not have much redundancy in its infrastructure and a major failure at any one point tends to congest their lines. The congested lines and reduced bandwidth coupled with their traffic shaping hardware may explain why it seems that there appears to be a cap when it may be just the traffic shaping hardware distributing the remaining/insufficient bandwidth about so that everyone at least gets some bandwidth rather than some at full while others at zero. This as well is also speculation but in my opinion, a more likely explanation rather than a focus throttle on high bandwidth users.
At the end of the day, we should not make any speculations until at least the APCN2 links are restored.