G'evening Chenquie and welcome to the forums!

if you experience any flakiness.. it could be your power supply. the quad core and the graphics board might want a bit more.
if you put another monitor on there, you might notice it.

as for leveling... most people will tell you to stay away from collection quests. 5x 20 of anything is just painful... unless you really must have the quest reward. kill quests are the best

limp along until you are 13 or 14 and start instancing... then it's just instance grinding for max xp/hour.

if you have any questions, please feel free to drop me a note.

good luck and welcome to the addiction!

Rob (keyclone developer)