what it does.

The PCI, and host (FSB) clocks run at different intervals. What setting it to host+33 does is add the FSB and the PCI clocks together to get the dram timing. Hence if you overclocked your computer it would add the host, let's say 105 to the PCI lets say 35. Making the dram timing 140. You are not overclocking anything if you use PC133 memory or better.