AMD Athlon 64 X2 microprocessor

Athlon 64 x2 are dual-core microprocessors best suited for running multiple applications on one computer. "X2" part in name is easy to explain - these processors incorporate two Athlon 64 cores on one die, hence it's an Athlon 64 x2. Having two-cores on one die comes at a price, though:

• X2 processors have much bigger die size - 218 mm2 for 0.09 micron processors with 1 MB L2 cache. For comparison, Athlon 64 with 1 MB L2 cache has almost two times smaller die size (112.9 mm2).
• Power consumption of two-core CPU is higher. For example, socket AM2 Athlon 64 X2 3800+ has Thermal Design Power 89 Watt, which is 27 Watt more than TDP of Athlon 64 3800+.

Athlon 64 X2 microprocessors have model numbers that show relative performance of the CPU. Because model numbers are calculated based on average of wide range of benchmarks, actual processor performance may differ for Athlon 64 and Athlon 64 X2 processors that have the same model number:

• X2 microprocessors will be faster than single-core Athlon 64 when running multiple applications.
• Single-core CPUs may be faster when running single-threaded programs. This happens because dual-core processors have lower frequency of each core, and, if the application doesn't utilize second core at all, the X2 CPU performs as single-core Athlon 64 running at lower frequency.