The high-end, enthusiast processors tend to get most of the press, with AMD and Intel releasing newer, faster processors on a regular basis, and redefining the performance landscape as a result. This does make for great headlines, but it also ignores the vast majority of buyers who simply cannot afford a processor that costs more than a mainstream PC. For most, the key element is value, and figuring exactly what the price-performance ratio is for a specific component.
Historically, Intel and AMD have targeted distinct brands at the various market sectors, and provided both entry-level and high-end processors. The strange thing is that up until today, AMD really didn't have a value brand. Intel markets the Pentium 4 and Celeron combination, while the AMD Duron simply drifted away over time. AMD currently has Athlon 64 and Athlon XP brands that essentially fill the markets, but the Athlon name has always been a performance-oriented one. Thus the AMD Sempron value brand was born, not only using existing Socket A technology, but forging entry-level inroads to Socket 754 as well.
The AMD Sempron release is kind of like a wedding, where the bride takes something old and something new. In this case, the Sempron 2800+ is the old, and the Sempron 3100+ is the new, but both are very well suited to the entry-level market. The AMD Sempron 2800+ and other Socket A models are based on the Thoroughbred core, feature 128K L1 and 256K L2 cache, and run on the 333 MHz front-side bus. This is basically a repositioning of the existing Athlon XP Thoroughbred core to the entry-level, while leaving the Athlon XP Barton models alone, at least for the time being.
Specifically, the Sempron 2800+ runs at 2.0 GHz, and AMD has also released Sempron 2600+ (1.833 GHz), 2500+ (1.75 GHz), 2400+ (1.667 GHz), 2300+ (1.583 GHz), and 2200+ (1.5 GHz) Socket A models as well. Physically, these new Sempron processors are duplicates of the existing Athlon XP Thoroughbred models, though not at the same clock speeds. One positive is the full compatibility with current 333 MHz Socket A platforms. This allows these Sempron models to slide right into an existing platform base, but the lower-than 333 MHz Athlon XP clock speeds also mean this is not really an upgrade line for current Athlon XP owners.
The Sempron 3100+ is a more interesting product release, as it is a totally new core revision, and uses Socket 754 as its platform base. The Sempron 3100+ is a Newcastle core variant, but instead of 512K of L2 cache, AMD has cut it in half to 256K. This is similar to the Newcastle release itself, and the impact of going from 1-MB L2 to 512K was not that big a deal, and in many cases, there was no performance impact. We have a feeling that the 256K of L2 featured on the Sempron 3100+ will have an impact, as AMD is targeting this model directly at value buyers. The Sempron 3100+ has no AMD64 capabilities, and is the first Socket 754 processor that does not support 64-bit computing.
The other physical specifications of the Sempron 3100+ remain consistent with current Athlon 64 Newcastle processors, including a 1600 MHz system bus, a 64-bit integrated memory controller supporting up to 400 MHz DDR, and a 0.13-micron process. The Sempron 3100+ has a core speed of 1.8 GHz, and is the only Socket 754 Sempron on the current AMD release list. In terms of platform compatibility, we tried the Sempron 3100+ on a few different Socket 754 motherboards, and it ran without issue, but we needed to get a beta BIOS file to ID the model number properly.
It should also be readily apparent that AMD needs to do something about their model number system, as we now have multiple processors using the same numeric code. The Sempron 2800+ shares its moniker with the Athlon XP 2800+ TB, Athlon XP 2800+ Barton, and Athlon 64 2800+. This duplicate number problem doesn't exist with the Sempron 3100+, although AMD will need to educate customers that a Sempron model number has a different performance basis than an Athlon XP or Athlon 64 model number. Surprisingly, this is one area that Intel managed to do right, and correctly separated the Pentium 4 and Celeron numerical scales.