Chip maker AMD has unveiled some more details about its next-generation 64-bit microprocessor, codenamed Hammer.

These developments should make for affordable superfast PCs early next year and servers, that will run current software just as fast s they run new.

There will be two versions of Hammer: 64-bit Athlons for single-CPU machines, such as standard desktop PCs and notebooks. These will be out by the end of 2002. And Opteron, a version built specially for multiprocessor systems, such as servers and high-performance graphics workstations. These will appear early next year.

Opteron and 64-bit Athlon chips will use Hypertransport technology to pass information around inside the PC, making the whole PC perform much more quickly and efficiently.

Hypertransport is the bus technology used in the Xbox to pass information around inside, and it will free up the bottlenecks that currently afflict PCs, especially when it comes to handling chunky wads of data for running video and streaming media.

Hypertransport has another benefit: it makes it easier to build motherboards — the electronic 'baseplate' in a PC to which are attached the CPU, memory, graphics board and other vital components. Simpler motherboards mean cheaper PCs.

The fact that there will be only two types of 64-bit chip for everything from servers to subnotebooks also makes the system builders' lives easier, which again should reduce the price to consumers once PCs with 64-bit chips in them are built in large numbers.

Microsoft has promised to deliver a 64-bit version of Windows XP for the AMD chips, but no one will have to throw away their old 32-bit software, promises Robert Stead, AMD's European marketing director.

AMD's 64-bit instruction set has been written so that it will run new 64-bit software but also 32-bit software — current versions of Windows and associated applications are all 32-bit — in what is called native mode. Intel's upcoming 64-bit processor, Itanium, will run 32-bit software through an emulator, so it will slow it down.