The chips offer better performance while drawing the same amount of power as existing quad-core Shanghai server chips, wrote John Fruehe, director of business development for server and workstation products at AMD, in a .

"Despite putting more cores in the processor, we managed to keep it in the same power and thermal ranges as our existing 'Shanghai' processors," Fruehe wrote. Shanghai chips draw between 45 watts and 105 watts of power and run at speeds between 2.3GHz and 2.8GHz.

Servers with Istanbul chips also showed better memory throughput and improved application performance in Windows Server 2008 through hyperthreading compared to previous processors, according to AMD.

Servers may include up to 48 cores by accommodating up to eight Istanbul chips, Fruehe said. Users will be able to plug Istanbul into existing sockets that run Shanghai chips.

The six-core chips are due in the second half of this year, Fruehe said. They will be manufactured using the 45-nanometer process. A company spokesman declined to provide further release details.