I currently have a pc with 2x8gb DDR4 ram. I have two open slots and want to add more. I have always heard you should get the same size sticks and even same manufacturer in a perfect world. I am wonderiung how much does this really matter? can I buy 2x16gb sticks and then have a total of 48gb? will this work? or do I need to get 2x8gb sticks? also the numbers related to timing do these need to match the sticks I already have? I know in a perfect world I would have 4 sticks of same size and brand but thats not the point here. Can I mix and match and will this be effective? what do I need to know? any feedback greatly appreciated!!