Same daytime "go-slooooow" problem here
I have the same problem - crawling dring the day (less than 1Meg speed) on a 10Meg business account

From late afternoon onwards I get my full 10M.
I have rebooted my modem, have had the port reconstructed by Telkom, and no, Afrihost, its not my line or my exchange, I have tried with various guest accounts from various providers and they all give me full speed during the day.
My speed this morning (and has been so for the last 2 weeks) is sitting on 40k!!!!!!
Browsing seems to be reasonably fast, but forget about downloading anything - its like I'm being throttled on this business account.
I have checked that my Protocol Prioritisation is off.
I am in the Bordeaux Randburg area.
Come on, Afrihost, please sort this out.
Afriman, please help with this.