Optimal Ram setup?

So I have a friend who has an Alienware Aurora ALX:
https://www.dell.com/us/p/alienware-aurora-alx/pd

That has 6 slots for ddr3 ram, according to the manual, with 1600 MHz XMP only 3 slots can be used.

It supports up to 24 GB, and 4gb per slot.
 

he said he'd rather have more faster ram, over just having a big number.
And he said his budget is $100-$150.
He mostly uses it for gaming, but wants to be able to edit videos later on. 

If possible could you guys help me find him the  best ram setup,
Some 'Cyber Monday' sale links would also be helpful!

-Thanks! 

what your looking for is 'triple channel' ram. btw, alienware is shitty now....

and you should be able to use all the slots.... but stick with 12g's.... 3x4g

http://www.newegg.com/Product/Product.aspx?Item=N82E16820231464

Sweet, Sounds good!