I don't have much in the way of help, but I get pretty much the same thing.
I'm running a P4 3.06@3.47 on a asus p4p800se and the mem options I get are auto, 266, 333. My cpu runs at 533fsb@default I'm at 604fsb with overclock. I'm using the same memory as you.
I assumed I needed a 800fsb cpu to get the option for max speed but I don't know. To answer your question, your ram is underclocked, but I don't know how to change it.
Edit: I also set mine to 333, if left on auto it selects 266??? Benchmarking shows that setting it to 333 gives better performance.
Also I tightened up my timings a bit I've set it to 2.5-3-3-7, I can't get my cas any lower than 2.5 it crashes badly when I try to adjust it. The tightened timings give slightly better performance with no errors in memtest.
If you want to screw with your timings make sure you're familiar with flashing your bios. I've had to reflash a couple of times now :^).