[win2kpro]

I don't believe the stepping of a particular speed is as important in this case as the "family group" to which the processor belongs.

The fastest Pentium 4 Socket 478 0.13 Micron, 800MHZ. FSB with a 512KB L2 cache was a 3.4GHz. processor SL793 which had a CPU ID of 0F29h.

All the Pentium 4 Socket 478 0.13 Micron, 800MHZ. FSB with a 512KB L2 cache except SL7BK had a CPU ID of OF29h. SL7BK has a CPU ID of 0F25h which would indicate an earlier family group as does SL6Z5.

The Dell site also indicates the board would support a Pentium 4 Socket 478 0.13 Micron 3.06GHz. processor with a 533MHz. FSB and a 512KB L2 cache.

This was a unique processor in the sense that this was the only processor Intel ever built with a 533MHz. FSB that supported HyperThreading. These processors were always in demand during those times because many of the socket 478 boards would only support a 533MHz. or 400MHz. FSB. In fact many of the earlier Pentium 4 socket 478 boards with the 845 series chipset would only support 400MHz. FSB.

There were only six variations of this processor built. They were;
SL6PG
SL6K7
SL6JJ
SL6SM
SL6S5
SL6QC

The SL6K7, SL6JJ, SL6S5, and the SL6SM had a CPU ID of 0F27h.
The SL6PG had a CPU ID of 0F29 and the SL6QC had a CPU ID of 0F29h.

Your machine theoretically per the Dell website should run any of these processors, however I believe it would most likely be able to run a SL6K7, SL6JJ, SL6S5, or the SL6SM because of the CPU ID being 0F27h rather than 0F29 or 0F29h.

As I previously stated these 533MHz. processors were somewhat rare and always sold for premium price.

Personally, if I were going to try another processor I would try one of the following. I believe the 3.06MHz. 533MHz. FSB and 512KB L2 cache are more likely to run without incident. There are most likely some available on eBay or maybe other websites, but I would make sure anything I bought had a warranty not to be DOA.

The SL7BK and the SL6Z5 are most likely more abundant, and less costly.

SL7BK 3.0GHz. 800MHz. FSB 512KB L2 cache HyperThreading CPU ID 0F25h
SL6Z5 2.8GHz. 800MHz. FSB 512KB L2 cache HyperThreading CPU ID 0F25h
SL6K7 3.06GHz. 533MHz. FSB 512KB L2 cache HyperThreading CPU ID 0F27h
SL6JJ 3.06GHz. 533MHz. FSB 512KB L2 cache HyperThreading CPU ID 0F27h
SL6S5 3.06GHz. 533MHz. FSB 512KB L2 cache HyperThreading CPU ID 0F27h
SL6SM 3.06GHz. 533MHz. FSB 512KB L2 cache HyperThreading CPU ID 0F27h