My son and I play online together on a wifi connection, no lag. 4Mb MWeb line, standard Telkom issue Netgear router, each of us on a 150Mb TP-Link USB dongle (Team Fortess 2, Counterstrike mainly)
It used to be that even if only one was playing we would get lag most days.
This helped:
- Set 2 PCs to highest priority in QOS on router
- In power management, set wireless adapters to "Maximum performance" (big difference)
- Ran a utility called SG TCP optimiser from speedguide.net. It auto configs your Windows network settings based on line speed (I think).
- In advanced wifi adapter settings, changed one of the params from "Performance" to "Wifi". Still don't know exactly what it sets, but made a HUGE difference (basically solved the lag issue).
Long story short, it's not just the ISP, tweaking your side can make the difference between "happy" and "crap".
BTW...was originally with Telkom, moved to MWeb because of crap Telkom service. That was my experience...