I've got a fairly old computer, a Tyan S1854 (also called 'Trinity 400') with a 700 Mhz Celeron on it. This board actually has the Slot 1 as well as the socket 370! This CPU is really barely adequate to run Windows XP, so I am thinking of upgrading to a real P III since they are now quite cheap. This board is supposed to to support up to 1 Ghz CPUs. But the manual was written in 1999 and is not absolutely clear that the Socket 370 supports any P III up to 1 Ghz, it only mentions the Celeron. The first thing I want to do is be absolutely clear that this Socket 370 interface is the same on all MBs and it will indeed take any FCPGA I Pentium III.

After that, I am curious about the difference in heat output between the Celeron and the P III. Is there are large difference at the same clock rate? Or will a heatsink designed for the Celeron handle a P III just as well? What about a somewhat faster P III like 800 or 933 Mhz? If this would not be sufficient, I need to figure the cost of a new heatsink into the upgrade because this board doesn't seem to have a heat sensor and I can't risk overheating. AND there is one more oddity. Searching for information I've found some reports that the default heatsink that came with the retail P III didn't fit on this board. If the spec for the design was well defined, I can only guess that some part of the board got in the way. Does anyone know what heatsinks are known to work on the Tyan S1854?

There is an option that will increase your processor from a 1.2ghz to a 1.4ghz Celeron. This works I have 13 computers, P-III's 500mhz, that I installed the adapter into. It is plug and play and it works.
I am running XP Professional with 768mb of PC100 RAM.
On ebay you can find the older P-III slot 1 adapters which they no longer make.
If you have your computer setup like you want, but need more processor this maybe what you need.

http://www.powerleap.com/PL-NeoT.jsp
http://search.ebay.com/search/search.dll?h...8%26catref%3DC6

Isn't the primary limitation of the Celeron the front-side bus clock? I think it would be easier to just put a P III at 100 or 133 Mhz FSB into the socket than get some special adaptor to connect a later Celeron than the board was designed for.

The only thing holding me back from just buying one on eBay right now (cheap!) is the question of heat output. The P III had more on-chip cache than the Celeron, right? Did this make a big difference in heat output?

8 of my computers have been running on this adapter for 3+ yrs. Never had a problem. I even had a Dell 266mhz PC66 running at 933mhz on a 1.4Ghz Celeron chip.
Heat has never been an issue. It is worth every penny if you just want to bump your processor and not get a new computer.