AMD Athlon II X2 microprocessor family

Athlon II X2 is the next generation of dual-core budget microprocessors, that superseded Athlon X2 family. The Athlon II X2 family was introduced in June 2009, four months before the launch of X3 triple-core and X4 quad-core Athlon II families. While many features of Athlon II X2 family and X3/X4 families are alike, there are two important differences between them. First, the X2 microprocessors have only two physical cores on a die. Almost all other Athlon II and Phenom II families pack 4 cores on a die, and, depending on a family, have from two to four cores enabled. With only two cores on a die, and without integrated L3 cache, AMD was able to significantly reduce the size of Athlon II X2 die - it's 30% smaller than the die size of triple- and quad-core Athlon II processors, and 50% smaller than the size of Phenom II processors. The other noteworthy difference between the dual-core Athlons and other Athlon II / Phenom II CPUs is the larger size of level 2 cache on Athlon II X2 microprocessors - 1 MB per core. Level 1 cache on X2s is 128 KB per core, which is identical to other K10 processors. Athlon II X2 microprocessors don't have level 3 cache.

Athlon II X2 CPUs integrate memory controller that works with DDR3 and DDR2 memory. DDR3 memory is supported only when the processors are used in socket AM3 motherboards. Despite the fact that the package of all Athlon II X2s has 938 pins, or two less pins than the package of socket AM2+ processors, Athlon II CPUs do fit into socket AM2+ motherboards, and, with proper BIOS support, will work in them. Like the Athlon X2 family, Athlon IIs also integrate one HyperTransport link, although it's clocked higher, at 2 GHz.

All members of Athlon II X2 family include the following features:

• SIMD (Single Instruction Multiple Data) extensions to instruction set - AMD's 3DNow! and Intel's extensions from MMX and up to SSE3. The processors also support 4 additional instructions that AMD dubbed "SSE4a".
• 64-bit instructions allow microprocessors to run 64-bit operating system.
• Enhanced Virus Protection, or NX bit prevents execution of malicious code in data memory by flagging that memory as "non-executable".
• Virtualization provides hardware support for, and acceleration of virtualization software, i.e special software that creates and runs virtual computer environments.

Athlon IIs have a number of power-saving technologies, marketed as PowerNow! 3.0:

• Cool'n'Quiet automatically reduces processor frequency and core voltage when idling, thus reducing dissipated power.
• CoolCore technology turns off parts of the processor to reduce power consumption.
• Smart Fetch Technology reduces unnecessary core wake-ups by sharing core data with other package cores before the core is stopped.
• Dual Dynamic Power Management – can manipulate voltage of processor core or memory controller independently from each other.

The Athlon II X2 family consists from microprocessors fitting three different thermal envelopes:

• Standard power - 65 Watt TDP.
• Low power - 45 Watt TDP. These processors have model numbers ending with lowercase "e", for example, "240e".
• Ultra-low power - 25 Watt TDP. Model numbers of these CPUS end with "u", and there model numbers are not comparable to model numbers of standard-power and low-power Athlons.

Model numbers of Athlon II X2 microprocessors consist from three digits with the first digit always "2", and an optional letter that signifies processor power - "e" for low-power, and "u" for ultra-low power processors.