AMD has updated its processor roadmap with plans for six- and 12-core server chips, in a move intended to recover lost ground on arch rival Intel. Meanwhile, workstation chips will move to quad-core within the same timeframe.

AMD said its first 45nm chip, a quad-core part codenamed Shanghai, is still set for delivery in the second half of 2008. This will now be followed in the second half of 2009 by a six-core processor codenamed Istanbul that will fit the same infrastructure as current Barcelona chips.

"Just as Barcelona fits within the same heat and power constraints as the dual-core Opterons, so Istanbul will be capable of the same thing," said Randy Allen, vice president of AMD’s server and workstation division. This will enable firms buying quad-core servers today to extend their life with extra performance, he added.

In 2010, the firm will introduce a new platform with both twelve-core and six-core processors, codenamed Magny-Cours and Sao Paulo respectively. While the six-core product will have all cores on a single die, AMD revealed that the 12-core part will be formed of two dies joined together, a strategy already used by rival Intel. The chips will also feature an extra Hypertransport link and support for faster DDR3 memory to boost throughput.

Allen said that AMD decided to move to six-core rather than eight-core because it could keep within the same power constraints as quad-core chips.

"Eight-core would have to go down in clock speed to stay within our existing three power bands, and the die size was also an issue. Six-core is the sweet-spot for what we wanted to attack," he explained.

However, Intel is preparing to release its six-core Dunnington chip in the second half of 2008, giving it a year's lead over AMD in this market segment.

By the time the 12-core chip hits the market, there will be a need for its level of performance, according to Allen especially in datacentres operating virtual workloads.

"We believe that at that point in time, there will be many workloads that will benefit," he said.

Allen contrasted these future datacentre chips with AMD's single-socket chips for workstations and entry-level servers.

"In this segment, workloads benefit from higher clock speeds rather than more cores," he said.

The roadmap here is for quad-core chips with a processor codenamed Budapest later in 2008 and a 45nm version codenamed Suzuka in 2009. However, Allen said it was too earlier to be specific about clock speeds AMD expected to deliver.