In a slightly surprising announcement, AMD has confirmed reports leaked earlier this month that the company is planning to make a three-core version of its Phenom processor.

However, AMD has still been very sparing on details, with no word on launch clock frequencies. The new range is expected to arrive in the first quarter of 2008, and will be based on the same technology as the Phenom quad-core processors.

Chip off the same block

Looking at the slides distributed by AMD, the triple-core CPU will still offer 512KB per core and 2MB of shared Level 3 cache like the quad-core version.

The processor will incorporate HyperTransport 3 and use the Socket AM2+ configuration, so will theoretically be backwards compatible with current Socket AM2 motherboards. However, compatibility is not guaranteed, and a BIOS upgrade will be necessary to recognise the new CPU.

AMD was candid about the fact that the triple-core Phenom will be produced on the same lines as the quad-core Phenom, making it quite obviously a quad-core die with one core disabled. Although this could be a way to use quad-core parts with one failed core, in reality it's likely to be a deliberate ploy to offer a wider range of options to consumers.

Pricing hasn't been set. But unsurprisingly, AMD claimed it will sit somewhere between the dual-core and quad-core ranges. This will give AMD a middle ground which won't be available to Intel's current configuration of two dual-core dies packaged together.

Xbox-friendly?

AMD also claims that since the Xbox 360 uses a triple-core processor, this will mean that it's triple-core processor will naturally be optimised to run Xbox 360 games ported across to the PC. A quad-core CPU could have a core sitting idle with these titles.

Since early Phenom benchmarks are pointing to it not being an Intel Core 2 killer, a triple-core Phenom could give AMD a price advantage over Intel in the mid range. But with Intel's Core 2 Quads already very competitively priced, AMD is going to have to be careful about positioning its new triple-core Phenom - particularly with Intel's 45nm Penryn just around the corner.