AMD coined the name from the Latin semper, which means "always, everyday", with the purpose of stating that Sempron was the right processor for everyday computing.
The first Sempron CPUs were based on the Athlon XP architecture using the Thoroughbred/Thorton core. These models were equipped with the Socket A interface, 256 KiB L2 cache, and 166 MHz Front side bus (FSB 333). Thoroughbred cores natively had 256KiB of L2 cache, but Thortons had 512KiB of L2 cache, half of which was disabled, and could sometimes be reactivated by bridge modification. Later, AMD introduced the Sempron 3000+ CPU, based on the Barton core (512 KiB L2-cache.) From a hardware and user standpoint, the Socket-A Sempron CPUs were essentially renamed Athlon-XP desktop CPUs. AMD has ceased production of all Socket-A Sempron CPUs.
The second generation (Paris/Palermo core) was based on the architecture of the Socket 754 Athlon 64. Some differences from Athlon 64 processors include a reduced cache size (either 128 or 256 KiB L2), and the absence of AMD64 support in earlier models. Apart from these differences, the Socket 754 Sempron CPUs share most features with the more powerful Athlon 64, including an integrated (on-die) memory controller, the HyperTransport bus, and AMD's "NX bit" feature.
In the second half of 2005, AMD added 64-bit support (AMD64) to the Sempron line. Some journalists (but not AMD) often refer to this revision of chips as "Sempron 64" to distinguish it from the previous revision. AMD's intent in releasing 64-bit entry-level processors was to further the market for 64-bit processors, which, at the time of Sempron 64's first release, was a niche market.
In 2006, AMD announced the Socket AM2 line of Sempron processors. These are functionally equivalent to the previous generation, except they have a dual-channel DDR2 SDRAM memory controller instead of single-channel DDR SDRAM. The TDP of the standard version remains at 62 W (watts), while the new "Energy Efficient Small Form Factor" version has a reduced 35 W TDP. As of 2006, AMD sells both Socket 754 and AM2 Sempron CPUs concurrently.