As for the choice of memory chips, I suggest you check the memory information in your notebook first, and you'd better buy the same memory chips as in your notebook, so that the compatibility is the best. If not, you must buy licensed memory chips, and the main frequency should be the same. Of course, it doesn't matter if it's different. The main frequencies of 1066 and 1333 and 1333 will be automatically downgraded to 1066. Never buy fake memory chips, which will lead to blue screen and crash.
Download WIN7 optimization master, there is a system slimming in the library, which will clear the installation package of your notebook system upgrade software and make the system run faster.