what about below 3.6 ghzThe Pentium 4 @3.6GHz & above would probably perform better than the e2140, but keep in mind that neither of them are very usable (let alone fast) by today's standards.
If you run the Pentium 4 around 3.4GHz it's unlikely to be noticeably different in performance to an e2140, but below 3.4GHz the e2140 at stock speed will perform better. Again, I would not recommend either of these processors, mainly because better ones are available for similar prices that are compatible with the same sockets.what about below 3.6 ghz