ram burned in?

The specs on my ram are CL2 up to 333mhz and CL2.5 at 400mhz. The first time I OC my processor to 400mhz fsb my system would not post at CL2. The thing is I have been able to slowly lower timings. I initially had my timings at 2.5-4-3-8. After I have "burned in" my system I have managed to actually lower my timings to 2-3-3-6! I flipped out when my system posted at C2 with 400mhz fsb. Is this normal?? I wonder if I will be able to lower my timings some more in the future....but I think I need to upgrade my crappy generic 300w PSU before I can OC some more. Has this happened to anyone else? Maybe my ram didnt like my mobo at first and now has grown to love it like I have? :D