I'm building a mini itx pc and the mobo only has two ram slots so I can't afford 16gb right now but I'll want to upgrade to 16 sometime in the future so it would be cheaper for me to get 1 8gb stick and just buy the same 8gb stick later. Would this slow down my computer at all or should I use 2 4gb sticks and then drop like $130 for a 16gb set