HP, the world's largest maker of personal computers, has quietly started to sell systems featuring microprocessors based on code-named Zosma design from Advanced Micro Devices. The chips are the first quad-core processors that feature TurboCore technology from AMD.

The new AMD Phenom II X4 840T and AMD Phenom II X4 960T are presently available inside HP Pavilion Slimline s5660f and HP Pavilion Elite HPE-400z personal computers from Hewlett-Packard, reports CPU-World web-site. The chips previously known as Zosma officially do not exist, but according to previous reports the microprocessors are sold only to system makers under special requests.

While the new quad-core processors are not significantly different from typical Phenom II chips with Deneb core, they feature TurboCore technology that can speed up two cores out of four (by 300MHz - 500MHz) when single-thread performance matter the most and two additional cores are not needed. Like other quad-core central processing units from AMD code-named Zosma chips are compatible with AM3 mainboards, feature 2MB of L2 cache, 6MB L3 cache and dual-channel DDR3 memory controllers.

Zosma is a modification of code-named Thuban six-core chips with two cores disabled. It is believed that the deactivated cores can be enabled on advanced mainboards. This is believed to be a reason why AMD is reluctant to supply Zosma chips in the channel as demand of enthusiasts may shift from six-core to quad-core microprocessors.

Exact specifications of the new microprocessors are not completely clear.

Tags: AMD, Zosma, Deneb, Thuban, Phenom, 45nm