The Athlon 64 X2 is the first native dual-core desktop central processing unit (CPU) designed by Advanced Micro Devices (AMD).

It was designed from scratch as native dual-core by using an already multi-CPU enabled Athlon 64, joining it with another functional core on one die, and connecting both via a shared dual-channel memory controller/north bridge and additional control logic.

[3] This is mostly due to the high overhead caused by constantly switching threads, and could potentially be improved by adjustments to operating system scheduling code.

These size requirements necessitate a more complex fabrication process, which further adds to the production of fewer functional processors per single silicon wafer.

The introduction of the F3 stepping then saw several models with 1 MB L2 cache per core as production refinements resulted in an increased yield.

'64' was omitted from the name of the Brisbane 'BE' series; the 64-bit marketing campaign initiated by AMD became insignificant once essentially all consumer CPUs became 64-bit processors.