Copied from response I entered on another post- thought it might be helpful to some:
Hey guys, re: lag issue-
Sometimes refreshing cures it at times I suspect the server might be running heavy.
Other times, tho, I can feel how hot my laptop's grafix proc'r is getting when I run around fast for too long- try this: I have used a can of compressed air and blown the COLD jet into the cooling vents (short little bursts over time, take it easy) and found it helps to cool down the hot stuff by removing the heat energy, as well as clearing the vent grates to increase cooling air thru-flow.
I run Vista w/ only 1GB RAM, and free breathing coolant air makes a difference.
Anyone else have any tips? This seems to be an issue to many at some time or another, and takes away from the fun of the game when it happens.