My subjective feeling is the machine is as responsive as with normal p3 settings. In any case, as soon as some load is detected the CPU will jump to a higher P state.
Perhaps interesting for you as well: I started a blog on the topic. See here http://underclockingundervolti...40-stable-k10stat.html
my P3 setting is enough for internet browsing (even YouTube)
It would be great if you post details with details on the 955BE.