I think that Pentium's are over rated. Here is one example. My friend has a P4 3.2 Northy OC'ed to 3.5 I gave him Super PI Mod and he ran the 1M test at 43 sconds. My Athlon XP-M 2500 @2.4GHz ran the 1M @ 43 seconds also. His clock speed is 3.5GHz with 533FSB and mine 2.4GHz with 400FSB.
Why in the world would my XP-M 2500 equal his P4 3.2 in this test? I am not even going to say how my 3700+ Sandy killed both of these CPU's @ 2.8GHz
I would give your new system a 7/10
If all you could afford at the time was a sempron than it was a wise decision over your old Pentium. Just my opinion.
EDIT: I made a mistake in quoting what CPU he had, it is actually a Prescott socket 478 @ 800FSB. Sorry!