Advanced Micro Devices spokesperson confirmed today that the company’s central processing units due next year in 754-pin and 940-pin packaging will be backward compatible with existing mainboards featuring appropriate CPU sockets.

In an attempt to boost processor’s bus throughput and better synchronize it with PCI Express, a new industrial standard for interconnections between PC components, AMD will next year allow its upcoming 64-bit desktop microprocessors for Socket 754, Socket 939 and Socket 940 platforms to work using 1000MHz HyperTransport bus. However, the push in HT speed will not affect compatibility of the new CPUs and already existing mainboards. According to AMD, all chips that sport 1000MHz (or 1.0GHZ) HyperTransport bus will work on mainboards available now that feature only 800MHz HT.

“HyperTransport is a flexible protocol. A current specification for it is 800MHz, yet some chipsets currently run 600MHz.  That is okay, the CPU just sets itself to the frequency the chipset can handle.  Likewise, a future AMD64 processor capable of 1000MHz HyperTransport, is still backwards compatible with mainboards that run their chipsets at something less than 1000MHz,” an AMD spokesperson said.

Generally, compatibility between components of different generations means a huge benefit for companies that deal with inventory, e.g. mainboard makers and PC makers.

“So, assuming you have got the same socket processor, e.g. Socket 754 or Socket 940, you will have backward compatibility with mainboards that are out there now,” he added.

According to the recent roadmap, next year AMD will release faster versions of its 64-bit microprocessors made at both 0.13 micron and 90nm nodes and will also broaden its 64-bit lineup with some low-cost offerings. The family of AMD64 products for desktops planned to be released next year contain chips for Socket 754 with 1MB of 512KB of L2 cache and single-channel memory controller as well as for Socket 939/940 with 1MB of cache and dual-channel memory controllers. Besides, there will be 754-pin CPUs without AMD64 instructions and marketed under AMD Athlon XP brand-name.

FSB and Socket compatibility are generally not the only terms of compatibility between a mainboard and a microprocessor. In case a mainboard cannot provide enough power or current for faster chip with higher consumption, such platform will not be able to work with the processor. For instance, Intel’s higher-end Pentium 4 “Prescott” processors will not be able to work with quite some Socket 478 mainboards that feature 800MHz Quad Pumped Bus because of unexpectedly high power consumption of Intel’s next-generation processors due to be released on the 2^nd of February, 2004.

Leading chipset designers, namely VIA Technologies, Silicon Integrated Systems, NVIDIA Corporation, ALi/ULi and ATI Technologies are expected to support new AMD64 products with their chipsets incorporating 1000MHz HT, PCI Express and other important features.