Intel’s 478 socket was the standard pin layout for many years and was used in both desktop and mobile options for most of their Pentium 4 and Celeron range. Socket 478 was replaced by Intel’s socket 775 as the standard pin layout for their desktop CPU range and for mobile options, socket 479 superseded socket 478. This is straightforward enough however there is a lot of confusion over what a socket 479 CPU actually is.
On Intel’s CPU sSpec index, in their official documentation, Intel refer to most thier mobiles CPUs as socket (/package) type ‘Micro-FCPGA’, regardless of processor family (range). This adds massively to confusion over what is and isnt a socket 479 CPU and what CPUs are compatible with what laptops and motherboards.
Socket 478 processors are so called owing to the fact they have 478 pins. One would therefore assume a socket 479 CPU has 479 pins however this is not the case. They infact still have 478 pins but in a different layout.
The differences of how the 478 pins are laid out all occurs in the same, gold triangle marked, lower right hand corner of the CPUs below. The following three images show the three layouts: