400mhz difference noticable or not?

[Foxhound]

I want to upgrade my S1's dvd-rw to a dvd+/-rw. Then I saw that Intel has released the pentium M processor up till 2,1 Ghz.
Since I have a 1,7Ghz I thought I might as well upgrade to 2,1Ghz if it is worth the extra 400Mhz.
But I really don't know IF 400Mhz is really a performce boost.
Anybody can shed some light on this issue?
Thanks in advance.:smileygrin:

[kee-lo_]

400Mhz is worth getting if you're going to be video editing or working on processor intensive projects.

Otherwise it's not worth it.