The term "Penryn" is sometimes used to refer to all 45 nm chips with the Core architecture.

Intel released an Apple-only Exxx chip on April 28, 2008 that increased the clock rate to 3.06 GHz as well as increasing the Front Side Bus to 1066 MT/s, and changed the Cache to 6 MB shared L2.

While it is used in desktop computers and has an E8xxx name, it uses the same packaging as mobile CPUs and is therefore considered a Penryn and not Wolfdale.

Mobile Penryns were later paired with the Cantiga chipset series which (among other enhancements) added DDR3 support.

The entry level Penryn-3M Core 2 processor is the T6xxx series, with 2 MB L2 Cache and begins with the T6400 at a clock rate of 2 GHz.

[6] As these require more power (45 W) and cooling than other Penryn processors they are not automatically compatible with all Centrino 2 notebooks.

Microsoft has released a microcode update (KB2493989) for Windows 7 that addresses several stability issues on selected "Penryn" and "Merom" CPUs.