As a whole, the Pentium 4 has a higher maximum performance than a Pentium III. The Pentium III performs the same as or better than Pentium 4 at the same clock speed, but the Pentium 4 has a higher max clock speed (which the Pentium 4 was designed for).
Pentium III was created in 1999.
There is no "Pentium R" processor. Knowing this, the biggest difference is that the Pentium III exists and the other does not.
The L1 cache in the Pentium III is SRAM.
The Intel Pentium III was released on February 26, 1999.
No. It is a higher-end version of the same processor, with a larger amount of L2 cache. It cannot be used as a replacement, since they use different slot / socket types.
Yes.
Possibly. "Celeron" doesn't refer to any particular processor. They are cost-reduced versions of the Intel Pentium II, Pentium III, Pentium 4, Pentium M, and Core 2 Duo. Assuming that your Celeron is based on a processor that is faster than the Pentium III, you shouldn't have any problems. If yours is based on the Pentium III, check the clock speed. A 1.2 GHz Celeron, for instance, is probably fast enough for a game that requires a 1 GHz Pentium III.Other factors, such as the graphics card of your system, may also be important.
No, you cannot.
Sort of. The processor is an Intel Coppermine-core processor that runs at 733 MHz. It is soldered onto the motherboard in BGA2 fashion, similar to that found in many older Pentium III and Celeron laptops. The processor can't be considered a Pentium III because it has half the L2 cache of a normal Pentium III at that speed and FSB. It's not a quite a Celeron either, though, since no other Celeron in that layout had that high an FSB (133 MHz in the Xbox vs. 100 MHz for other mobile Celerons. It thus sits somewhere in between in terms of performance.Architecturally, it is no different than a Pentium III, though. Linux applications written for the Pentium III can run without modification on the Xbox.
The AMD K6-III and early Athlon processors are roughly equivalent in speed and performance. Via C7 processors, although released much later, are close in terms of performance to a Pentium III.
They are no longer manufactured.