More memory could help but even if your buying an identical stick there is a small chance that it may not work well together and even a chance it may not boot. Since you already ordered it try it out and see if it helps. Getting a better CPU should help, something like the 2600(K) or 3770(K) should help in more CPU intensive titles and can usually be found used for a decent price. The SSD won't really do much for your games besides maybe making the loading screens faster but is good to have nowadays since your general use will speed up a bit.