I currently have 64 GB of DDR4 RAM clocked at 2666mhz. Unfortunately, that is the fastest my CPU can handle (according to intel) and 64 GB is the maximum amount of memory the CPU can handle.
For Christmas, I figured it makes more sense to upgrade capacity over speeds (seeing as my original set was 16 GB 2400mhz) without really considering or looking into it. So far it’s awesome, and I can compact files drastically smaller then before, and editing videos is a faster process, but I still think about speed.
Rather than google it, I would rather ask people who have experience