Since the day Sempron CPU from AMD was released one of the most frequently asked question is “afterall, what is the difference between Sempron and Athlon XP?”
Sempron is a slower Athlon XP (the exception goes to the Sempron socket 754 versions, which are an Athlon 64 with less L2 memory cache; these models use socket 754 pinout, thus requiring motherboards originally developed to Athlon 64, having a greater performance then socket 462 models). Originally Sempron socket 754 didn’t have the 64-bit extensions available on Athlon 64, but since July, 2005, AMD introduced the 64-bit instructions on these processors. So, the socket 754 Semprons listed below can be found with or without the 64-bit extensions. The models with 64-bit extensions enabled have the letters “BX” as the two last letters printed on the CPU package.
The difference in performance between Sempron and Athlon XP occurs due to the numbering system used to designate the processor’s speed, which is differente for each processor. A Sempron 3000+ isn’t faster than an Athlon XP 2800+, even though it has a greater number. The processor numbers can only be used to compare CPUs in the same product line, i.e., you can only compare Sempron to Sempron and Athlon XP to Athlon XP.
To fully understand this issue, take a look at the tables below. As you can see, a Sempron 2800+ is slower than an Athlon XP 2600+ 333 and a Sempron 2600+ is slower than an Athlon XP 2500+. To make the comparison, you have to watch the internal clock, the external clock and the L2 memory cache size.
This naming scheme used by AMD is really confusing. As you can see there are three Athlon XP 2600+ models with completely different technical specs, even though they use the same name.
| Processor | Internal Clock | External Clock | L2 Memory Cache | Socket |
| Sempron 2200+ | 1.50 GHz | 333 MHz | 256 KB | 462 |
| Sempron 2300+ | 1.58 GHz | 333 MHz | 256 KB | 462 |
| Sempron 2400+ | 1.67 GHz | 333 MHz | 256 KB | 462 |
| Sempron 2500+ | 1.70 GHz | 333 MHz | 256 KB | 462 |
| Sempron 2600+ | 183 GHz | 333 MHz | 256 KB | 462 |
| Sempron 2800+ | 2 GHz | 333 MHz | 256 KB | 462 |
| Sempron 3000+ | 2 GHz | 333 MHz | 512 KB | 462 |
| Processor | Internal Clock | HyperTransport | L2 Memory Cache | Socket |
| Sempron 2500+ | 1.40 GHz | 800 MHz | 128 KB | 754 |
| Sempron 2600+ | 1.60 GHz | 800 MHz | 128 KB | 754 |
| Sempron 2800+ | 1.60 GHz | 800 MHz | 256 KB | 754 |
| Sempron 3000+ | 1.80GHz | 800 MHz | 128 KB | 754 |
| Sempron 3100+ | 1.80 GHz | 800 MHz | 256 KB | 754 |
| Sempron 3300+ | 2 GHz | 800 MHz | 256 KB | 754 |
| Sempron 3400+ | 2 GHz | 800 MHz | 256 KB | 754 |
| Processor | Internal Clock | External Clock | L2 Memory Cache | Core |
| Athlon XP 1500+ | 1.33 GHz | 266 MHz | 256 KB | Palomino |
| Athlon XP 1600+ | 1.40 GHz | 266 MHz | 256 KB | Palomino or T-Bred |
| Athlon XP 1700+ | 1.46 GHz | 266 MHz | 256 KB | Palomino or T-Bred |
| Athlon XP 1800+ | 1.53 GHz | 266 MHz | 256 KB | Palomino or T-Bred |
| Athlon XP 1900+ | 1.60 GHz | 266 MHz | 256 KB | Palomino or T-Bred |
| Athlon XP 2000+ | 1.66 GHz | 266 MHz | 256 KB | Palomino or T-Bred |
| Athlon XP 2100+ | 1.73 GHz | 266 MHz | 256 KB | Palomino or T-Bred |
| Athlon XP 2200+ | 1.80 GHz | 266 MHz | 256 KB | T-Bred |
| Athlon XP 2400+ | 2 GHz | 266 MHz | 256 KB | T-Bred |
| Athlon XP 2500+ | 1.83 GHz | 333 MHz | 512 KB | Barton |
| Athlon XP 2600+ | 2.13 GHz | 266 MHz | 256 KB | T-Bred |
| Athlon XP 2600+ 333 | 2.08 GHz | 333 MHz | 256 KB | T-Bred |
| Athlon XP 2600+ | 1.90 GHz | 333 MHz | 512 KB | Barton |
| Athlon XP 2700+ | 2.16 GHz | 333 MHz | 256 KB | T-Bred |
| Athlon XP 2800+ | 2.25 GHz | 333 MHz | 256 KB | T-Bred |
| Athlon XP 2800+ | 2.08 GHz | 333 MHz | 512 KB | Barton |
| Athlon XP 3000+ | 2.16 GHz | 333 MHz | 512 KB | Barton |
| Athlon XP 3000+ 400 | 2.10 GHz | 400 MHz | 512 KB | Barton |
| Athlon XP 3200+ | 2.20 GHz | 400 MHz | 512 KB | Barton |