My little K was originally 2g ddr3 1333 Memory , I replaced it with 4g ddr3 1333 Kingston Now only one 4g memory is used. I thought it would be faster, but it backfired. These days, it was not much faster, and it crashed once. It never crashed before. One more question, wireless mouse Somehow, I always get stuck. Not before... I am very puzzled. I can solve...... I have checked the security of the memory module, which is genuine.