Optimizer would not help, may even have opposite effect. You may have 16GB but how much of tha is usable and free ? Check in Task manager > Performance > Open Resource monitor > Memory tab.
By the way,about the ReadyBoost, I have one 64 GB 3.0 USB and I would like to try it! But in Registry I don't have the EMDMgmt key ,to edit the ReadyBoost option!