What to look for when buying a RAM

Ragnarous

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Sep 15, 2013
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Hey guys, I'm in need of a new RAM. Right now I have this one:
https://www.gskill.com/en/product/f3-10666cl9d-8gbxl-

My next candidate with a new mobo and CPU are these:
https://www.gskill.com/en/product/f4-3000c15d-16gtzr

I know that 3000Mhz over 1333Mhz is much better but my old ones have only 9CL whereas the new ones have 15. Is less CL better? If so, why are the newer models more laggy?

I know that more mhz equal more speed, but no idea aside from that what to look for when buying a RAM. Please enlighten me what I need to know in general :)

Thank you!