Review on Patriot Signature 8GB DDR3 (2x4GB) CL11 PC3-12800 (1600MHz) 240-Pin DDR3 Desktop Memory Kit - Enhanced for SEO by Andrew Grimes

So first of all, yes, you have to press firmly to make the RAM cards snap into place. And yes, it's best to include matching pairs. They installed great but booting was a little painful. I kept getting memory errors. So I just put in one card (there were 2, I bought 2), booted it into the bios, put in the second one and rebooted and so on with the rest. Finally he recognized it. (This is a Dell XPS 8700 computer) But one day they seem to work fine. I doubled my RAM and it shows up correctly in the BIOS.