I got a 2mb with telkom as my isp(yes I've tried other isp's aswell). All have similar results and my ping spikes are in the afternoon from about 5/6 till 10 and it goes from 100-600. My friend that lives about a km has the exact/extremely similar spikes and he is with mweb. Telkom tech came today and basically said my line is fine and offered no solution , not surprised...
http://www.speedtest.net/my-result/3007281515
http://www.speedtest.net/my-result/3007281515