Wow, I missed a thread months ago. Sorry for not keeping track. For running your memory at higher speeds you will need to access your BIOS and select higher timings.
These instructions are specifically for the MSI G41 motherboard, the steps will be very similar for other BIOS's though
Power down the computer and wait a little bit for everything to settle. Power on the computer and press the "del" key repeatedly to access the BIOS. Once in the BIOS you can only navigate with the keyboard arrow keys, select "Cell Menu" (top right corner) and press enter.
Navigate to "Advanced DRAM Configuration" and press enter, select "Manual" and press enter. Modify "FSB/DRAM Ratio" until "Adjusted DRAM Frequency(Mhz)" is 1333, modify CAS and other settings according to your memory manufacturers specifications. Press Esc a bunch then select save and exit when prompted. The computer will reboot.
Congratulations you are now running at 1333 mhz memory. If the system does not reboot, you will need to manually trigger the BIOS reset jumper on the motherboard. This is in a different location on each revision so check your manual and locate this first.