Listen folks. It has nothing to do with your SIM card, nor your phone. The reps at rogers, I for one, ASSUME it could be the sim card, but really, most of the reps cannot differentiate an incompatible SIM with a compatible one, so they send you out a new one anyways, just to get you off the phone because they really don't know what the cause is and they have no hands on the status of the networks and network problems other than what is posted in library by the actual IT department, which do not directly communicate with the centers.
To sum it up. Rogers 3G network is garbage! and that DNS issue is not isolated to the metro area, it's here too in Newfoundland. DNS resolution is extremely slow, even with OpenDNS, which means it's their switches that are garbage and most likely being bogged down. Rogers thinks they had solved the problem by throttling the 3G bandwidth to ~3Mbit and the upstream to less than 150K, (My assumption), however, that isn't working.
From my guess is that the request is sent to Rogers networks, which cache that request then caches the pages and sends it to your device, making it appear you have a fast connection. :P
Anyways, sometimes I find the EDGE network a lot faster..especially in the DNS resolution area.