We often see Mac prototypes with strange motherboards, but rarely models with an Intel CPU, especially a CPU that was not officially offered by Apple. Indeed, an old forum post shows a PowerBook with a Pentium M.
The Pentium M is a mobile Intel processor released in the early 2000s when the Pentium 4 was unusable in laptops. It had low power consumption for its time, with very decent performance, and the Core Duo (used in the first Intel Macs) is essentially a dual-core Pentium M. Apple did not use the Pentium M in Macs, but it did in one product: the 2006 Apple TV.
Apparently, the person owned a development Mac, built before the release of the MacBook Pro. They mentioned that the Mac displayed 1,072,300,032 bytes of system memory tested OK (so 1 GB of RAM), followed by the message: Intel Mobile Calistoga CRB Framework Implementation Copyright (c) 1999-2005 Intel Corporation. All rights reserved. Intel (R) Pentium(R) M CPU BIOS Version: 0.0F, 10/11/05 For Evaluation Purposes Only.. Calistoga was the code name for a chipset of that era, the i945.
No visible markings
No red motherboard
The stickers indicate that it is a prototype
The old photos show a PowerBook or MacBook Pro with no markings on the front. The motherboard, seen from a distance, looks quite standard, but the back shows the usual prototype Apple stickers. I tried to contact the person behind the posts, but it’s really old…
