I don't think that the difference really matters. The Celeron's cache is smaller, but faster. In theory depending on the memory access profile applications could run faster on one of these CPUs.
In practice the difference won't be very big.
An example from 1998: http://www.tomshardware.com/reviews/big-cpu-shoot,84-2.html
Quake 2 massive1 demo.
Pentium II 333 MHz: 56 fps
Celeron 333 MHz: 55 fps
(K6-2 scores are with 3DNow patch, otherwise those would be lower.)

Thx! PII-333 could bei upgraded to Celeron-433/Slot1, 533/S370.
That would be an Upgrade to the actual used PII-333 😀

A similar comparison:

Pentium II, Deschutes SL2QF, half speed 512kB L2
400/100 MHz: PCbench 62,4 // Quake 105,6

Pentium III, Coppermine, QH31ES, full speed 256kB L2
400/100 MHz: PCbench 59,4 // Quake 104,9

Pentium III, Tualatin-S, QEL8ES, full speed 512kB L2
400/100 MHz: PCbench 65,1 // Quake 115,6

Re: 133 MHz Challenge - 5th/6th gen CPU per clock performance

I did some comparisons in this thread, 400MHZ Shootout! PC Chips vs. Dell! Pentium II vs. Celeron!, between a Pentium II 400 and a Celeron 400. The thread is a comparison of 2 systems, but sixth post down I compare the processors in the same system. The processor performance is very similar, within 3% depending on the benchmark. The major difference was the change in bus speed affecting memory performance.

I ordered a celeron 400 slot in the us. this must be better then my pII-333. we will see.

Depending on the task you give it, you might be hard-pressed to notice the difference.

Celeron 400 <> PII-333 no difference? sure?

Actually, now that I think about it, there should be some difference between them. In the past I've noticed sharper desktop performance from the Celeron than the PII.