|I don't know how you arrived at 9GB. It is running in triple channel mode?|
Is it possible your CPU is overheating & throttling back?
Has your BIOS been tweaked for best performance? (since it's a Gateway, there may not be much you can do with it)
Is Win7 tweaked for best performance?
Have you uninstalled any useless software, managed your startup apps, & installed a lightweight antivirus (NOT McAfee or Norton)?