My speed is about 1/4 of normal speed (normal is over 4Mbps), and I also attribute it to the school holidays.  Normally my day time and evening speed is about the same, but not at the moment.  The alternative to having lower speed during holidays is to always have low speed.  In South Africa they are now "trialling" 4Mbps, most ISPs offer only something like 256k, 384k, 768k and 2M (can't be bothered checking the exact speeds just before bed time).

XNet runs primarily a VoBB service as well as broadband.  VoBB will get the best quality service, normal web browsing comes second and everything else will come after that.  They do act very quickly to expand bandwidth when required.  They need to in order to sustain VoBB and BB service quality, and did so a few weeks/months ago.

Last weekend I was at my in-laws which are rural, I was amazed at the internet speed day and night.  But they would not get the same congestion (where they are) as most suburban exchanges during the holidays.  They simply do not get the sudden large numbers of school kids sitting at home surfing the web.  For 3 days I spent a lot of time on their internet connection and not once did it slow down.

On the side:
All South Africans will be amused by the acronym ANC, as it also stands for African National Congress which is a political party that played a significant roll in ending the apartheid era.  You will jokingly be told not to use the ANC, that they are trouble.  (Note I'm neutral over the issue, do not label me as a racist.)