The 'Merom' Core 2 Duo mobile microprocessor Intel will ship with 'Santa Rosa', next year's Centrino upgrade, will not be quite the same Merom that it's due to launch in August. The two versions of the CPU will not be pin-compatible, it has been claimed.

According to a presentation allegedly given by Intel to Taiwanese notebook contract manufacturers and cited by Chinese-language site HKEPC, the Santa Rosa Merom will have a slightly different pin-out than the version for 'Napa', the current incarnation of Centrino. The two interconnects are dubbed Socket P and Socket M, respectively.

The first two pins in the first row of Santa Rosa Merom's 478-pin layout are missing. With Napa Merom - and, indeed, the Core Duo line-up - it's the first two pins of the layout's first column that are missing. The report reckons the Santa Rosa part's other corners are taken up with "sacrificial corner balls", though is doesn't say what they're for.

Santa Rosa is due to be launched in Q2 2007 and is expected to ship alongside four new Core 2 Duo mobile processors: the T7700, T7500, T7300 and T7000. The Meroms due next month are the T7200, T7400 and T7600, all of which will still be available come Q2 2007.

Roadmaps have shown the presence of the T5500P in the Santa Rosa timeframe, even though there's a T5500 due in Q4 2006. The later part's suffix suggest as Socket P version of the, by then, already available Socket M release. ®