The curcial website does say 4gb max memory but i can confirm the dell 518 does work perfect running 8gb of memory just make sure to get the right timing which is 66618

I have heard that the 518 might run with 16gb but i didnt want too take the chance and have too return products knowing 100 that it would run on the 8gb i bought this 8gb memory upgrade for a home computer that was crashing fairly often due to a memory issue