Memory comes in as DDR3L-1600 CL11 1.35v and set to 11-11-11-28, and reports dual channel. I haven't run a memory benchmark on it and don't expect any surprises. No BIOS overclocking and it's locked to the JEDEC standard speeds on the modules. I added CORSAIR 16GB (2 x 8G) 204-Pin DDR3 SO-DIMM DDR3 1600 (PC3 12800) (Model CMSO16GX3M2C1600C11), so that I have 24 GB total (removing 4 GB). I noticed a distinct performance improvement, but Windows 8.1 seemed less stable, crashing periodically. With some research and debugging it is now rock stable (I would hope that grabbing current updates would result in the same). To upgrade the speed you would have to remove ALL Ram in the machine (pairing faster RAM with the DDR3 1600 will only result in all your RAM running DDR3 1600 (PC3 12800) and you would experience no gain for your extra expenditure (supposedly gaining access to the memory on the motherboard's other side will void the warranty, unless you have an ASUS authorized facility do it for you). All of this combined with my experience with 8.1 becoming less stable would lead me to recommend just upgrading the amount and staying with DDR3 1600. On the plus side I am able to run high end 3D CAD (CREO/PRO-E and Catia v5 and v6) fairly well considering the lack of certified drivers and NON-ECC RAM, as well as enterprise class PLM (Product Lifecycle Management) development and integration and the accompanying engineering end user development and deployment. And I can play some games from time to time. Just my 2¢.