This cut down on a lot of the lag that you would otherwise have experienced in these places, although I feel obligated to note that these cities were so crowded during classic WoW that people with low-end systems might not have noticed about WoW Gold.

In a roundabout way I guess you could say that flying mounts and the need to "finish" absolutely everything that a player might conceivably see is one of the great unheralded issues Blizzard deals with while trying to make sure that the game remains playable.

Anyway, I got off track there. Truthfully, Broncofan, unless it is something that everyone on your realm complains about regardless of the system they are running, it is likely to be your computer and not the game that is causing the problem, even if you are only having problems in Dalaran. The quickest fixes you can make that will have the largest impact:

Turn down the options on how far you can see things. Your computer will stop trying to load objects and terrain past a certain distance about WoW Gold, which means that instead of loading that giant circus worth of players and mounts in Dalaran, it will only load it up to a certain distance. Still, Dalaran is so crowded that this might not make a big difference there, but you will notice a difference outside of the city. Of course, you may not even need to do this outside the city, so...catch-22 about WoW Gold.

This actually helped me a LOT: cap your framerates, at least while you are in town. The ingame command is /console maxfps n, where n is the FPS beyond which you do not want your computer attempting to load about WoW Gold. Most people will tell you to /console maxfps 30; I have had more success with 25. Capping it below that is possible, but in a video game, the human eye can more easily distinguish between 25 and 20 FPS than 30 and 25.