I have a 8 GB PC3-12800 (DDR3-1600) ram chip in my Hp 500-164 i want add more ram if i put 2 PC3-14400 (DDR3-1866) ram chips in, will they work with my old chip or do they all have to all be 1 type and speed. they are both supported by my computer according to them. http://support.hp.com/us-en/document/c03933829