Old Celeron Vs. New Celeron
The left one is the old Celeron PPGA. On the right you see the new Celeron with Coppermine core and ISSE. As you can imagine, there is hardly any performance difference between the old and the new cores, unless you are using applications that benefit from SSE. Please take a look at the following graphs.
Old Celeron Vs. New Celeron: Scaling
As you can see, the performance advantage of the Celeron 566 over the "old" Celeron 533 is exactly as we would expect it. There are no performance jumps.
Here you can see clearly that 33 MHz higher CPU clock generates 4 SYSmark points or approximately 5 to 6% more performance. The Celeron models between 366 and 533 MHz scale fairly in line. Now see the jump between the 533 and 566 MHz model: The step is 11 SYSmark points or approximately 11% more system performance. Obviously, the software used by Sysmark 2000 benefits from the SSE instruction set of the new Celerons, as the game benchmarks did not run faster at all, unable to take any advantage of the Streaming SIMD Extensions.