12GB at 9-9-9-24 or 8GB at 8-8-8-24. Does RAM Latency matter?

myaccount1234

Honorable
Sep 12, 2015
99
1
10,645
I bought an 8GB kit from crucial and it came yesterday. The kit has the same specs and voltage as my stock computer ram 4GB Kit but only slower memory speed and even different brands. I installed them and the computer works fine and running with 12GB. I ran the computer with only the new ram at 8GB to test it out for a few hours. The timing the computer was running at 8-8-8-24 665 MHz x2. My motherboard on this stock HP computer limited my clock speed at 1333 MHz and I was not getting the 9-9-9-24 1600 MHz clock speed the new ram should have been doing. Now I figured I try using the old 4GB same speed and voltage ram that is a different brand and at a lower speed of DDR3-1333 @ 9-9-9-24. Now the computer computer is clocked at the same speed as the limited 8GB kit DDR3-1600 @ 9-9-9-24 from crucial. Am I better off with 8gb 8-8-8-24 665 MHz x2 or 12 GB 9-9-9-24 1333htz? I thought mixing ram kits brands was a bad idea so that is way I am asking this question and I wonder is the different in speed Latency matters.