It's not officially supported, the 5520 only officially supports 4GB sticks for a total of 8GB of RAM. However, this post suggested that some 8GB sticks work with a BIOS update, some don't. http://en.community.dell.com/support-forums/laptop/f/3518/t/19468207?pi41097=2 I personally wouldn't take the risk, and would stick to 2 4GB sticks instead.
It's not officially supported, the 5520 only officially supports 4GB sticks for a total of 8GB of RAM. However, this post suggested that some 8GB sticks work with a BIOS update, some don't. http://en.community.dell.com/support-forums/laptop/f/3518/t/19468207?pi41097=2 I personally wouldn't take the risk, and would stick to 2 4GB sticks instead.