Well, going off marketing clock speeds, it's jumping 1100. Thats a smidge over a 50% jump, in theory. Will you notice that difference, probably, but there is a good chance it won't be as big as you are hoping for.

My system upgrades tend to be quite large and the difference is easy to see. I went from a 300 Celeron -> 433 Celeron laptop -> P3 800 desktop then decided the quick upgrades were getting expensive. I then held onto the 800 until 2 years ago, jumping to a 2.26 P4. My next jump I plan on getting an Athlon 64 4000+ sometime next year, along with a new video card and such.