Please explain this more to me.
I'm looking for a cheapo set up for a HTPC (XBMC) and a cheap, dual-core setup like this may just fit the bill.
Here's a little write up about it. The second core unlock is not guaranteed since it may be defective. Like some other AMD multicore CPUs, defective cores wil be disabled and the CPU sold as a lower model. If they need more inventory for lower models AMD will disable good cores to meet the demand.
Sempron 140 Unlocks to Athlon II X2
It has been done over and over again, and each time new AMD processors successfully unlock disabled cores (dubbed "defective"), it only makes us wonder if it is a deliberate attempt by the company to make buying its cheaper processors potentially rewarding. It has been discovered that AMD's recently announced Sempron 140 single-core processor can be transformed into a dual-core Athlon II X2 series processor with a simple, well-known trick. This comes as no surprise, as the "Sargas" core the processor is based on, is made by disabling one core on the Regor dual-core die.
The trick requires a motherboard with AMD SB710 or SB750 southbridge that supports the Advanced Clock Calibration feature. Not all motherboards, however, support this mod. By simply enabling the feature in the BIOS setup program, the system will be able to address both processor cores, with the complete feature-set of Athlon II X2. The staff behind the feat over at Thai techsite VModTech tested for the unlocked core's stability with much success. At 3.71 GHz (13.5 x 275 MHz @ 1.536 V), the processor stood SuperPi, WPrime, and WinRAR bandwidth tests. Validation can be found here. At around $40, here's the cheapest ticket to a dual-core processor that looks $80 Intel processors in the eye.