The A series of processors love RAM with higher clock speeds, so i've heard. I'd look for something 1866 or higher. Look for something of reputable brand (G.Skill, Kingston, Crucial or Corsair would be a few)
Don't worry about if the RAM has heatsinks on it or not, it's just for looks these days.http://www.newegg.com/Special/ShellShocker.aspx?cm_sp=ShellShocker-_-20-231-527-_-01302013_2
Newegg actually has a sale on G.SKill 1866 RAM right now! Doubt if you'll catch it in time but good luck.