A stable FPS still doesn't give you 0% unhits. My FPS is a solid 500 (does not jitter) and yet I still get the odd unhit, although this time I know it's due to a high ping (around 300ms, and pj is stable). But even so, the overall percentage of unhits is still very low...
Edit: On second thought, perhaps it isn't my connection. But the occasional unhit is still there.
Edit: On second thought, perhaps it isn't my connection. But the occasional unhit is still there.