AMD Athlon 64 Core Explanation Note: No processor is guranteed to do anything apart from operate safely at advertised specifications. Although some cores have reputations of high overclockability, chips of the same core vary based on speedbinning, fab location, and week and stepping numbers. A common question which seems to be asked is the difference between the numerous cores which AMD offers on the Athlon 64 lineup. Each core offers a variation of improvements over its predicessor, and this will explain the relations between the current cores offered for Socket 939 Athlon 64s. One of the large differences between AMD cores is the process size. The process size is measured in nanometers (1 nm = 0.000000001 meters). Smaller process size is in theory a superior core, simply because the circuits consume less power, and uses less current as it can charge faster. Consider a 130nm core, and a 90nm core. Imagine the 90nm core is a 200mL cup, and the 130nm core is a 300mL cup. Not only can the 200mL cup fill faster, it fills up with far less liquid or voltage, therefore it uses less power and produces a smaller heat output. The only problem with smaller process size is the fact that as transitors get smaller, the insulation also gets smaller and current can have a tendency to leak, or give out excess heat output. AMD has not reached this problem as of yet and their 90nm cores are still energy and heat conservative, however the Intel "Prescott" suffers from this problem. AMD currently has five single cores availible to the socket 939 family; Newcastle, Clawhammer, Winchester, Venice, San Diego. AMD also offers multicores: Manchester and Toledo. Newcastle Newcastle is one of the older AMD Athlon 64 cores, being brought to the socket 939 family from socket 754. Newcastle chips are based on the 130nm process, and have the largest power consumption and heat dump overall next to the Clawhammer core. They've got the normal Athlon 64 cache size of 512KB. Newcastle is availible in chips such as the 3000+, 3200+, 3500+, and 3800+. It's a dated core and as far as overclockability goes, don't expect much more than 400MHz on air. I really would stay away from this core as I don't think there's any difference in price between it and the more power conservative 90nm cores. Clawhammer This core is another one that migrated from the socket 754 family, and assumed the role of dealing with the high end processors in the family, such as 4000+ and FX series processors. It is also avalible in 3400+ format however. It's nearly identical to the Newcastle except it pumps out more heat, consumes more power, and has a larger 1MB L2 cache. Like the Newcastle, this core has bitten the dust recently, and is outshown in both overclockability and overall performance by newer 90nm cores. Winchester This is the first native socket 939 core that AMD introduced, and is also the first core to boast the 90nm process size. The Winchester is near identicle to the Newcastle, however it has a smaller heat dump and consumes less power. Again, a modest 512KB L2 cache. These cores scored some big points in the overclocking catergory early on, you should expect about a 400-600MHz increase on these cores. Unfortunetely however, the 90nm process wasn't perfected and couldn't sustain higher clock speeds, and was only availible up to 3500+. A Winchester generally caps at around 2.6-2.8GHz(if your lucky)mostly 2.2-2.5GHz since the silicon couldn't support higher clock speeds. The Winchester has been revised, and replaced with the "Venice". Note: Some Motherboards require an updated BIOS in order to use 90nm cores. Venice The Venice is notorious for it's ridiculous power and voltage conservation, reaching clock speeds as high as 3GHz with little overall vcore increase. The Venice uses an improved intergrated memory controller which can account for all 4 DIMM slots running at 400MHz. Previous memory controllers would underclock the RAM to 333MHz if all four slots were in use. The Venice specifically fixes the silicon problem found in the Winchester and can handle higher clock speeds. It's also the first AMD core to add SSE3 instruction sets, the third iteration of the SSE instruction set for the IA-32 architecture. It is a SIMD instruction set. If you are purchasing a midrange processor, get a Venice based chip. Note: Some Motherboards require an updated BIOS in order to use 90nm cores. San Diego Once the silicon problem found within the Winchester was fixed, the 90nm process could support higher clock speeds. AMDs high end cores such as the 4000+ and FX series were stuck on the 130nm Clawhammer core since the 90nm silicon could not support them, however, using the Venice architechture, the San Diego, with a larger 1MB L2 cache, was born. The San Diego is identical to the Venice, same instruction sets and memory controller, as well as same notorious overclockability. The introduction of the San Diego effectively migrated all Athlon 64 cores to 90nm process technologies. If you are buying a high end core, the San Diego is for you. Note: Some Motherboards require an updated BIOS in order to use 90nm cores. Manchester This core is the lesser of the two multicores avalible, with a 512KB L2 cache on each of its cores. The Manchester consumes a lot of power and gives off quite a bit of heat despite running on a 90nm process, however, still achieves impressive overclocks ranging between 2.6-3GHz. Note: A BIOS update is required to use AMD multicore processors. Toledo Toledo, in theory, offers the fastest processor on the market at the moment, the 4800+. Toledo offers a 1MB L2 cache on each of its cores, and uses a 90nm process. It consumes more power than the Manchester and gives off quite a bit of heat dump, but still provides impressive overclockability. Note: A BIOS update is required to use AMD multicore processors. To summarize, in my personal opinion the only two cores worth considering right now are the Venice, and the San Diego. The previous cores are outdated , and price is relatively the same when comparing to their predicessors. As far as multicore processors go, multithreaded applications to take advantage of Toledo/Manchester are a rarity. Performance gains over single core processors are neglible, and the price is still too much for what they are offering. I suggest waiting 6-12 months before purchasing a multicore processor. just if your wondering, i like the venice core!