[vrinsd]

The PCI chipsets of this time were really really buggy, that's why.

They got better as time went on but it really took a number of years before people could get reasonably high-performance, reliable PCI implementations. For x86, aside from AMD's Irongate (750/760) chipsets (K7-era) and nVidia (nForce), pretty much only Intel had PCI working reasonably. ALI, VIA and SiS PCI implementations always had weird issues and quirks.

PCI-IDE adapters are another good example -- VIA's PCI IDE had all sorts of issues, if you wanted high performance PCI IDE, it worked best with Intel.

It's not that different with modern PCIe-SATA either (history repeats), Marvell PCIe/SATA adapters have lingering oddities.

[rasz]

Wasnt Irongate build on licensed VIA chipset IP, and same deal with nForce being Acer/ALI/ULI?

[vrinsd]

No, Irongate was very much internally developed by AMD. AMD was well aware of the "sketchy" nature of ALI/VLI/ULI/SiS and knew it was giving them a really bad rep so they undertook their own designs.

AMD chipsets were not as successful in the marketplace because unsurprisingly the AMD-chipsets cost more than the Taiwanese ones, and motherboard vendors (who are almost all based in Taiwan) stuck with their existing vendors. The dual-socket AMD machines (K7-based) pretty much all had the 760MPX on it because I think only AMD had a multi-socket chipset that was reliable.

AMD also inhereted a lot of DEC engineers, so it was no surprise that K8-era their 'HyperTransport' was really 'Lighting Transport', developed at DEC.

Interestingly, Micron had also developed a chipset for AMD in this era but never released it.

nForce was also not re-licensed from ALI/ULI that I recall but I have far less insight here. nVidia at the time had a 'total system play' in mind so they were attempting to do GPU/audio/network/chipsets for AMD & Intel and got designed into original Xbox (x86-based). Jensen I think used NRE money from MSFT to fund a lot of the nVidia chipset work.

[rasz]

>No, Irongate was very much internally developed by AMD.

My confusion comes from wiki entry for AMD-640 https://en.wikipedia.org/wiki/List_of_AMD_chipsets#AMD-xxx I assumed 741 was further development based on 640.

> AMD was well aware of the "sketchy" nature of ALI/VLI/ULI/SiS

From my limited experience in practice AMD-751 was more problematic than KT133/133A. Those were still the times when hardware reviews had sections dedicated to "Stability". For example https://www.anandtech.com/show/718/5

"Even when running the DDR SDRAM at CAS 2 settings, the system did not crash once within 24 hours of our stress tests. We continued to run the stability tests and finally the first crash occurred after 34 hours of operation. Considering that this is FIC's first try at a DDR board we were very impressed with the stability of the AD11."

Personally I dont remember many vendors sticking with AMD chipsets after switch to Socket A, at least in Europe it was all VIA with some ALI/SIS. As for price its all on AMD, nobody forced them to manufacture at Dresden. If chipset was so strategic AMD should have sold it with minimal/no margin. The way I see it AMD was just seeding the market making sure to avoid chicken and egg problem.

[hakfoo]

I wonder if there was also some business sabotage in effect.

It would have been extremely tempting for Intel to pressure motherboard manufacturers with some subtle messages like "Nice AMD750 board, too bad we don't have any more 440BX chips for you."

The Athlon debuted with only like three compatible mainboards, and two of them were minimally rebadged versions of the AMD reference design. Of course, it was still too compelling of a platform to ignore, and everyone got on board soon enough. But if R&D had stayed away from the Athlon market for an extra 6 months or a year, that could manifest in worse board design and optimization for quite a while.

[hakfoo]

ULi got subsumed by nVidia shortly after PCI-Express became the norm.

They made a chipset which offered a fairly compatible AGP-like slot alongside PCI-e, and one with two full x16 slots when this otherwise required a very expensive nForce board. So of course, nVidia immediately blocked SLI support on it.