System Builder's Guide 2005
For AMD, you have the Sempron, Opteron 64, Opteron 64 X2, Athlon 64, Athlons 64 X2, Athlon FX series and even the older Athlon XP. The FX series being the fastest single core CPUs to date. There are the Semprons, but they are more along the budget lines and should be avoided when you're planning on any good gaming.
The Athlon XPs are old and out of date now, and you will be hard pressed to find them in some stores now. The Opterons are expensive and are meant for servers/workstations. They can be a viable option though, and there will be an example of one in the systems later on in the article. There are new Opterons that come in the 939 socket. These are the Venus (single core) and Denmark (dual core) variants.
Then there comes the socket. The older sockets like 462, and even 754 should be avoided. 462 are completely obsolete, and 754 lacks the new features like Dual Channel memory and support for the newer cores, athought the new Turions use that socket. Now if you just surf the web and check emails, a socket 754 will be all you need, as you don't require the computing power. Socket 939 is the newest out, and has all the new features like support for Dual Core, the new cores and all that fun stuff.
The socket AM2 (The newer form of socket 940. Other 940 pin chips will not work on socket AM2) will be out some time in 2006, and will have DDR2 support. If you have an existing 939 board that is top of the line, don't freak out about having to switch to AM2. It's only DDR2, which has no huge gain over DDR. But if you are changing over completely, well go AM2.
So now that we have our socket, what are we going to put in it? Dual cores are slowly becoming an advantage in games. Game makers are starting to take advantage of the second core, and there are some video card drivers out that support the second core. If you like to do lots of Windows based things, and you multitask like crazy, a dual core is for you.
If you have a lot of money to spend nad are not into overclocking, get an FX. The newest being the FX-57. The FX-51, and FX-53 should be avoided as they are older and are socket 940, which is expensive. You can get an Athlon 64 that will be just as fast for half the price of these older FX series.
For games nowadays, you should probably have at least a 3200+ Athlon64. If you are overclocking, get a 3000+ (3000+ production has stopped, but are still around) or a 3700+ San Diego. But if you are not and you like to stay stock, get at least a 3200+. The reason for this is because, where parts like video cards are so powerful, you need to have a powerful CPU to keep up with graphics card(s). Otherwise you have just wasted money by buying a nice powerful video card which is limited by the CPU.
Also with CPUs, there are cores to consider too. The newest single cores out are the "Venice" and the "San Diego". The difference between these two is the Level 2 Cache size. The more the better, but not by much. But it does crank the price up a bit. So when you buy a CPU from AMD, go with these cores as they are newer and have some better features like improved Integrated Memory Controller (IMC) and SSE3 support. The dual cores, also have different cores called "Manchester" and "Toledo". Difference again is size of Level 2 Cache. Again, more cache means more performance. As mentioned above about the Opterons, they come in dual and single core, but they always have 1MB cache. There will be more on cache below.
Here's a link to show the prices of AMD CPUs.
An AMD Athlon Socket 939 core.