When you have a CPU with 800MHz FSB (200MHzx4 because its an Intel), your RAM will usually work at 200MHz (400 MHz DDR or PC3200).
You also have to consider that the FSB:SPD ratio is 1:1.
The FSB:SPD ratio is on the Northbridge. This will enable you to run RAM at a frequency that doesnt match up exactly to your FSB, as in the case with a 400MHz FSB CPU.
Now because this CPU has a FSB of 400MHz (100MHzx4), you would think that the RAM would run at 100MHz (200MHz or PC1600). This is not the case, though. THe FSB:SPD ratio is no longer 1:1. Your RAM runs at 166MHz(333MHz DDR or PC2700).
In short, dont worry about it