While researching the Ultimate Museum PC it was hard to avoid the Tualatin, the final 0.13-micron incarnation of the Pentium III. With speeds up to 1.4GHz and 512KB on-chip L2 cache, a pair of PIII-S Tualatins should provide decent oomph. There’s just one problem—there doesn’t seem to be any Intel chipset which would support dual Tualatin processors.
Motherboards with dual Tualatin support do exist, but nearly all of them have either ServerWorks or VIA chipsets. While it is possible to run a Tualatin with an Intel 440BX/GX chipset, this requires an adapter or a modified processor. The 440BX/GX chipset is (in theory) fundamentally incompatible with Tualatin processors due to a difference in signaling voltage levels (AGTL vs. AGTL+).
Ironically, Intel itself sold server boards (SDS2, SAI2) with dual Tualatin support… boards built around chipsets from ServerWorks (the ServerSet III). This inevitably led to a few conspiracy theories.
The suspicion was that Intel did not want to promote Tualatin processors because they made the Pentium 4 look bad. A 1.4GHz Tualatin performed as well as a faster-clocked Pentium 4 and used plain PC133 SDRAM instead of expensive RDRAM.
Intel’s position at the time (2001) was clearly schizophrenic: There was a huge push to sell Pentium 4s, power-hungry and under-performing processors. For laptops, Intel initially had no choice but to sell Pentium IIIs. For servers, there were Pentium 4-based Xeons, but again power-hungry. For low-power 1U rack-mount servers, the Tualatin Pentium IIIs were an excellent choice.
For reference, the TDP of a 1.4GHz Pentium III-S was 32.2W (less than the 34.5W of a 600MHz Katmai Pentium III) while the TDP of an early desktop 1.7GHz Pentium 4 was 64W. The contemporary Foster Xeon processor had a TDP of 56W at 1.4GHz.
It is a question whether the Tualatin Pentium IIIs might have scaled past 1.4GHz or truly hit a wall, especially in light of the (much) later Pentium M. It’s certain that they didn’t get much love from Intel, with questionable “features” such as having multiprocessing support disabled in all but the server versions. Based on the performance of Tualatins relative to Pentium 4s, it’s no wonder there was suspicion Intel just didn’t want the Tualatins around.
Whatever Intel did back in 2001-2002, nowadays a Tualatin 1.4GHz Pentium III-S is quite easy to find. I myself ended up with a small pile of 1.26 and 1.4GHz Tualatins and a question: What’s a good board for these babies?
Dual Tualatin Boards
There is a handful of motherboards which support dual Tualatin processors. There are Intel’s own server boards, the SDS2, SCB2, (both extended ATX) and SAI2. All are based on the ServerWorks ServerSet III HE-SL chipset. This is a high-performance chipset with support for interleaved SDRAM memory; the boards support up to 6GB RAM. The boards come with relatively poor on-board graphics (ATI Rage XL) and no AGP slots; this is typical for server boards.
Supermicro built several P3TDE boards based on the ServerWorks HE, HE-SL, and LE chipsets; the P3TDE6-G with a 2x AGP Pro slot. Supermicro also offered P3TDD boards based on the VIA Apollo Pro 266T chipset. The P3TDDE board came with an AGP Pro 4x slot which should be capable of supporting quite fast graphics cards.
There were several other dual Tualatin boards based on the VIA Apollo 266 chipset: The AOpen DX37, MSI Pro266TD Master (MS-9105), and Iwill DVD266. The Iwill was rather unusual because it supported DDR SDRAM, although with questionable benefit.
Back in August 2001, Anandtech had a nice review of the then-current dual Socket 370 boards with an emphasis on desktop boards. The most exotic was the Acorp 6A815EP, the only one based on an Intel chipset (815EP), despite the fact that the 815EP did not officially support multiple processors. Many boards were based on VIA’s earlier Apollo Pro133 chipset, often with the dreaded 686B southbridge.
I must admit being tempted to get one of the ServerWorks-based boards, just to see what Tualatin Pentium IIIs can do with a high-performance chipset. It’s truly a shame that Intel did not build any dual Tualatin chipsets… but ultimately just a footnote in the annals of corporate stupidity.