Would you attribute Hard drive reading / writting, Processor speed, RAM or Internet connection to be the main factor in the lag you encounter in larger citys? I assume it could be a collection of all of those things, but is there one that's more crucial than the others? I'm fine outside of the cities and in instances, and during non peek hours it's certainly not as bad but it happens

Q6600, 4 gigs of ram, 3 hdds, 5Mbs dsl connection