I know they had an issue with Kingston Hyper-X and it probably won't come back until they have an update, but I am not sure whether it was exclusively that ram module or any other 1600mhz. It may be a situation where they only install that ram because they get it as part of a deal from their supplier. There is one person on the forum who did a review of the optimus v 15.6: https://www.pcspecialist.co.uk/foru...e-to-First-use-and-Beyond&p=216237#post216237
The Kingston ram was replaced by 1600mhz Samsung branded ram.
I would get in touch with PCS to make sure other ram modules are supported though, it would be silly if they weren't as Haswell can utilize 1600mhz ram, being incompatible would be shooting yourself in the foot