.. I am just getting Dual Core. My venerable Biostar T6100-939 now sports an X2 4400 + in place of the single core 3500 +

Installation

It was a good time to clean out all of the dust collection areas inside the case, including the CPU fan and heatsink, which will remain the same as the X2 runs cooler than single core variants.

Removal of the old CPU and the fitting of the new one was a breeze. The AMD 939 heatsink mounting follows the same basic design as early PC processor heatsinks in that it is a single spring tension bar which clips to lugs on either side of heatsink cradle. Reassembly was easy too, and the machine was re-cabled and readied for first boot.

Powering up

No problems here. The BIOS reported the CPU correctly, and Windows 7 sorted out the drivers. A required reboot seated them, and a glance into Task Manager showed both cores working. It really was that easy.

Performance

Performance monitor was next on the agenda and a refresh saw the CPU index rise from 4.3 to 4.9. Memory crept up too from 4.6 to 4.9. The increase was not huge, and huge was not expected, but the machine multitasks better than it did previously. Webcam performance is way better, even when running  a multiplicity of other applications, and I am pleased with the increase in power.