What computer to get

I am looking to upgrade from an old gaming laptop to a laptop with a better battery life mostly, but is still very fast and has a reasonable GPU setup, around my price range of 750 USD or less. I have found two compelling options that blend enough performance and battery life for my needs at...

Basically, I have a Pentium G3258 processor that supports DDR3-1333MHz RAM. Can I have my RAM clocked to a different frequency though? I'm not asking if you can use 1600MHz ram in a 1333MHz supported processor, I know it will automatically underclock, but can you use any different frequency than...