Hi
Celeron processors have certain high-end processor features disabled (like dual processing or multiprocessing).
Celeron processors are slower than similar-clocked Pentiums due to smaller L2 cache size.
You need to check the bus speed of the processors you are using to ensure that the memory modules match.
Celerons sometimes have slower bus speeds than their nearest Pentium III counterparts.
I take it that you are using coppermine processors (since there is no Celeron 1.1Ghz in a slot one pack that I'm familiar with)?
The PIII PGA (coppermine) was available with a FSB of 133
http://www.cpu-world.com/CPUs/Pentiu...ppermine).html
The Celeron PGA (coppermine) was available with a FSB of 100
http://www.cpu-world.com/CPUs/Celero...ppermine).html
Given that you are using PC100 RAM (stated in your description)
and not PC133 RAM the the Celeron would be the obvious choice, since the PIII 933 has a FSB of 133.
The optimal solution would be to use the PIII 933 with PC133 RAM.
For further reading I recommend that you take a look at:
www.cpu-world.com which has a very extensive repository of processor descriptions and images.
Regards
Chris