If the fact that the Thunderbird isn't really going to be available in a Slot-A package got you, you're going to love the chipset/motherboard support for the new Thunderbird & Duron processors.
The Duron will obviously only run on a Socket-A motherboard. The only two chipsets that will officially support the Socket-A platform are the AMD 750 and the upcoming VIA KZ133. The KZ133 is nothing more than the KX133 with support for Socket-A. Once again, the KZ133 is nothing more than the KX133 with support for Socket-A.
This means that there is a possibility that the KX133 chipset may not work with Socket-A CPUs, which is quite unusual because AMD is claiming that their AMD 750 will work just fine with them. At the same time VIA will be pushing for the Socket-A KZ133 chipset, so it makes sense that they wouldn't want to push the idea of Socket-A backwards compatibility with their KX133 platform.
The Athlon (Thunderbird), as we mentioned earlier, will primarily be a Socket-A solution and will thus be limited to the same chipset solutions as the Duron. However, we also mentioned that AMD will be producing Slot-A Athlon (Thunderbird) processors for OEMs that have AMD 750 based designs and aren't willing to qualify a new setup in order to move to Socket-A.
So there is a chance that current AMD 750 based motherboards will be able to run the new Athlon (Thunderbird) processors with the proper BIOS updates and provided that you can actually get your hands on a Slot-A Athlon (Thunderbird). There is no word as to whether or not KX133 based motherboards will be able to work with these processors, although it doesn't really make sense if they weren't able to work on them unless VIA completely forgot to incorporate a portion of the AMD 750's design into the KX133.
Update 05/04/2000: We just received the following note from AMD's Drew Prairie:
"...the only thing I thought i
would point out is the part where you say kx133 boards likely won't support Thunderbird. They won't. Our plan is to only make the Slot A TBird part available to our OEM partners who have requested a Slot A TBird part and plan on using it in their current systems featuring the AMD-750 chipset."
The idea of a Socket-A to Slot-A converter (à la the current Socket-370 to Slot-1 converters) has come up more than once over here, and we decided to ask AMD about it. Officially, AMD is neither endorsing nor supporting such a converter card although they wouldn't deny that it could be done. The only reason Intel is supporting a Socket-370 to Slot-1 converter is to ease the transition to FC-PGA 370, but we have already established that AMD isn't looking to make this a smooth transition to Socket-A at all. We may see Socket-A to Slot-A converter cards in the future, but it is very clear that AMD wants to make this move to Socket-A as quickly as possible, allowing no time for any transitional tools such as a converter card.
The assumption has always been that, upon the release of the Thunderbird, everyone would be running motherboard platforms with DDR SDRAM support, but unfortunately, that won't be the case.
Remember that we just said that the only two available platforms for Socket-A processors at the launch of the Duron/Thunderbird will be the AMD 750 and the VIA KZ133. We already know that the AMD 750 doesn't support DDR SDRAM, and as we made it a point to mention twice above, the KZ133 is nothing more than the KX133 with support for Socket-A.
This translates into no DDR SDRAM platforms available for the Athlon at the launch of the Thunderbird – don't kill the messenger.
It won't be until the release of the Mustang in Q3/Q4 that we will see the introduction of the AMD 760 chipset with DDR SDRAM support, but at the same time, we should see the AMD 760MP (also known as the AMD 770), which will be the first multiprocessor capable Athlon chipset allowing for 2-way Athlon configurations.
At some point during that time, ALi and SiS should be releasing their Athlon chipsets, but realistically, don't expect either of those two companies to bring anything to the table that you will want to take over the AMD or VIA chipsets.