This is a program specifically made for AMD/ATI the results vary depending on the specs/OS of the user. I freed up 400 MB of RAM. MAKE SURE to READ the SUPPORT section. It might help, it might not, use on own caution. (mainly because it's possible it might close anti-virus)
http://game.amd.com/us-en/drivers_fusion.aspx?p=1
Video card is okay, ram is low, but if you are lagging simply by typing the post, you probably just have something wrong PC i.e viruses, spyware, old hard drive.