Does anyone know any information on the release/price and features of the socket 939 motherboard? Will 939 have ddr2 and PCI Express capabilities? Also is it true that the 939 will implement dual channel memory for the Athlon64's as well as the A64-FX. Will A64's right now fit in a 939 mobo, from a socket 754 motherboard and will the 939 be compatible for A64's and A64-FX?

arguably too many questions close together there

If AMD make the Socket 754 processors compatible with socket 939 that would be awesome, I don't think it's impossible, I bet it can be done

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MSI KT8 NEO
Athlon 64 3200+ @ 2.0ghz
1.0 GB DDR PC3200
2X 160 GB HDD
Hightech Excalibur Radeon 9800 Pro Iceq 128mb
( Core 425 MHz and Memory 380 MHz )

It is unlikely Socket 939 will support DDR2, mainly because a future DDR2 dual channel controller embeeded in the A64 chip would require more pins than available in socket 939 (939 pins), so DDR2 requires a new socket. Thatīs the downside of integrating memory controllers into CPU's - a new type of memory, a new processor, or in case of dramatic architecture changes (DDR to DDR2), a new type of socket + a new processor. The upside is an extremely high memory performance due to the fact that the memory controller works at the speed of the processor core - in a A64 3200/2GHz, the memory requests are sent to the controller at a whooping 2 GHz in opposition to only 800 MHz (4x200MHz) in a P4 system (chipset 865/875).
Yes, itīs true, the new Athlon 64 will feature a dual channel memory controller - thatīs the reason for the extra pins (754 to 939). Other improvement is the fact that these new A64 won't need registered /ECC memory - much more expensive and slower, but more reliable regarding data integrity and error correction - a requirement of the previous socket 940 (A64 FX, Opteron). Thatīs the reason for lower pin count of socket 939.
Of course, AMD cut down L2 cache on A64 from 1 MB to 512 KB and kept it 1 MB on FX series (now also on Socket 939, not requiring registered memory thus becoming faster memory performers). Why? To keep Athlon 64 FX a little bit faster than Athlon 64 to justify a processor in the price range $650-$800. If they kept the 1MB L2 cache of the former Athlon 64, there would be no reason for Athlon FX to exist, because there would be absolutely no difference between the two series. The previous A64 series (socket 754) will not fit in a socket 939, nor the previous FX series (socket 940). Both new series (A64 and FX) will be packaged in the new socket 939, and gradually, socket 754 (single channel unbuffered memory) and socket 940 (double channel registered memory) will be discontinued.
My regards.

In order to answer the remaining questions, and regarding the PCI express support, that support does not depend from the socket format or the processor design, but only depends from the chipset. Certainly we will see PCI express support for socket 939 processors from chipset makers such as VIA or nVidia, in the near future.

Reference prices for new AMD Athlon 64/FX processors (1000 quantities/OEM unit aprox.) :

FX-53 / 939: $800
3800+ / 939: $720
3700+ / 754: $710
3500+ / 939: $500

For more information check:

http://www.techreport.com/reviews/2004q2/athlon64-3800/index.x?pg=1

or

http://www.sudhian.com/showdocs.cfm?aid=541