by , 7:40 AM EDT, May 22nd, 2006

Apple ultimately chose to replace the PowerPC processors at the heart of the Mac with chips from Intel, but it was also working with PA Semi as a possible supplier, too. According to The Register, PA Semi was developing a low power, high performance chip that was to be compatible with existing Mac software and the Altivec math co-processor.

The PA6T-1682M, due in the third quarter of 2006, looked to be a logical choice for the PowerBook: a 2GHz dual core processor with two DDR2 memory controllers, a 2MB L2 cache, and PCI Express support, that consumes only 7 watts of power. In comparison, Intel's Core Duo uses over 20 watts of power.

PA Semi's chips would have prevented the massive application rewrite developers are working through, too, since PowerPC-native applications would likely have run on them without modification. Apple and PA Semi engineers were working together to ensure a smooth transition.

PA Semi's production time frame, however, may have been too far out for Apple. The PA6T-1682M wouldn't be shipping in volume until 2007, leaving the PowerBook without a major performance upgrade for another year. Application developers may have played a role in the decision to use Intel chips, too, if they felt more comfortable writing code for the Core Duo processor.

Apple may be out of PA Semi's future, but the chip maker isn't letting that slow it down. With an extra US$50 million in investor funding, the company now has its eye on the embedded chip market for storage devices.