The only way to compare performance is through benchmarking them both stock vs. oced.....that you get a vision on how much performance boost you've gained and what not.....
I went up to 1.6 and it dumped, I had to reset it . It is my first oc, I dont want to do it to my amd quite yet, Just testing out this overclocking thing
Your Celeron 1.3 sounds like a Tualatin core. It has 256K of L2 cache and is 8 way associative.
I run a box with a 1.4 Ghz Celeron Tualatin core @ 1.68 Ghz for a 20% overclock. Your overclock represents a little over a 15% overclock and is not bad for free. If you put a more effective HSF combo on it you might be able to get a little more. IMO, however, investing anymore into that CPU isn't worth it. Sit back and enjoy your accomplishment!
Good job!