The Anatomy of a Server - The CPU

All systems need a CPU to operate them. With CPUs, the general rule is the faster the better, but typically an increase in speed corresponds to an increase in price. AMD and VIA are the only commercial competitors to Intel. The Intel Pentium and Celeron CPUs hold their value, even when used for at least two years after their first release. The Pentium Xeon is Intel’s flagship server processor. It offers better performance on enterprise-size servers, but at the cost of hundreds of dollars. The AMD family of CPUs includes the Athlon and Duron. The Duron is considered a direct competitor to the more economical Intel Celeron chip. However, even with the same processor speed, the Duron’s front-side bus (FSB) is twice as fast as the Celeron’s FSB (200 MHz vs. 100 MHz), making it an infinitely better bargain because the Celeron is usually more expensive (even used). The FSB is a more direct link to the system’s memory, and thus a higher FSB increases the system’s performance (discussed further in Chapter 4).

At first glance, the two CPU sockets on these two motherboards may appear to be the same.

However, a side-by-side analysis reveals that they are two different species of form factors; the left is the AMD Socket A, and the right is Socket 370, typically used for Intel Processors. The VIA C3 chips also use the Socket 370 form factor.

There are specific motherboards for matching CPUs. Depending on its age, an AMD Athlon or Intel Pentium sold on eBay doesn’t necessarily mean that they’ll fit your motherboard (see Figure 8). Here’s a short list of the most popular CPUs and their dedicated sockets:

• The newer Pentium 4 chips use either Socket 423 or Socket 478, while Pentium III chips (which also came in two flavors) originally used.
  
• Slot 1, and then moved to the more compact Socket 370. That’s also true for the Intel Celeron.
  
• The newer AMD Athlon and Duron processors, from about 800 MHz and up, use Socket A. However, there is some overlap with the older Slot A (see Figure 9). You can purchase an AMD Athlon 800MHz processor in both Socket A and Slot A. These are two very different forms.
  
• The form factor for the VIA Cyrix C3 processor (600 MHz to 1 GHz) is also Socket 370, and is usually compatible with any motherboard that accepts an Intel Celeron.
  
• The only processors capable of working on a dual-processor motherboard are the Pentium III, Pentium 4, and Athlon MP. The socket may match other processors, and you may be able to use, for example, a Celeron on a dual Pentium motherboard, but only one. There are a few Socket 370 Celeron motherboards, but they’re not the best choice for dual processing because of limited FSB speed.

Pentium 4 and AMD Athlon XP chips may cost over $100 alone, so consider your needs: Is this a file server with minimal workload, or do you plan to install the corporate materials management application on it, too? Do you need that much speed? The cost of dual processing is easily justified when working with applications that require high processing, such as those that perform 3-D graphics rendering, videoconferencing, or DVD encoding, or when working with databases that are queried hundreds of thousands of times a second. That coupled with a high-speed Small Computer System Interface (SCSI, pronounced “scuzzy”) drive will take almost anything you throw at it—but do you need it?

A dual-processor motherboard and a few high-speed CPUs will run you in the hundreds of dollars alone (Figure 9). True, I’m all for more power and speed, but the accountant usually doesn’t see it that way. Let’s follow specifications based on Table 1 for our hunting excursion. I’ll also consider speed and power and let you know when and where a dual-processor motherboard or a SCSI hard drive may benefit you.

Figure 8 The AMD Athlon Processor: “Socket A” on the left and as the older “Slot A” on the right

Figure 9 Dual-processor motherboard