Since the 486, processor upgrades have been relatively easy for most systems. With the 486 and later processors, Intel designed in the capability to upgrade by designing standard sockets that would take a variety of processors.

Thus, if you have a motherboard with Socket 3, you can put virtually any 486 processor in it; if you have a Socket 7 motherboard, it should be capable of accepting virtually any Pentium processor (or Socket 7-based third-party processor).

This trend has continued to the present, with most motherboards being designed to handle a range of processors in the same family (Pentium III/Celeron III, Athlon/Duron/Athlon XP, Pentium 4/Celeron 4, and so forth). To maximize your motherboard, you can almost always upgrade to the fastest processor your particular board will support.

Because of the varieties of processor sockets and slots—not to mention voltages, speeds, and other potential areas of incompatibility—you should consult with your motherboard manufacturer to see whether a higher-speed processor will work in your board.

Usually, that can be determined by the type of socket or slot on the motherboard, but other things such as the voltage regulator and BIOS can be deciding factors as well.

For example, if your motherboard uses Socket 370, you might be able to upgrade to the fastest 1.4GHz version of the Pentium III. Before purchasing a new CPU, you should verify that the motherboard has proper bus speed, voltage settings, and ROM BIOS support for the new chip.

If you are unable to install a faster processor directly into your system, a variety of third-party solutions are available, including adapters that can help first-generation Socket 423 Pentium 4 motherboards use Socket 478 processors, faster Socket 370 processors for older Slot 1 motherboards, and so on.

Rather than purchasing processors and adapters separately, I usually recommend you purchase them together in a module from companies such as Evergreen or PowerLeap (see the Vendor List on the DVD). Upgrading the processor can, in some cases, double the performance of a system.

However, if you already have the fastest processor that will fit a particular socket, you need to consider other alternatives. In that case, you really should look into a complete motherboard change, which would let you upgrade to a Pentium 4, Athlon XP, or Athlon 64 processor at the same time.

If your chassis design is not proprietary and your system uses an industry-standard ATX motherboard design, I normally recommend changing the motherboard and processor rather than trying to find an upgrade processor that will work with your existing board.

OverDrive Processors

Intel at one time offered special OverDrive processors for upgrading systems. Often these were repackaged versions of the standard processors, sometimes including necessary voltage regulators and fans. Unfortunately, they frequently were overpriced, even when compared against purchasing a complete new motherboard and processor.

They have all been withdrawn, and Intel has not announced any new versions. I don't recommend the OverDrive processors unless the deal is too good to pass up.

Processor Benchmarks

People love to know how fast (or slow) their computers are. We have always been interested in speed; it is human nature. To help us with this quest, various benchmark test programs can be used to measure different aspects of processor and system performance.

Although no single numerical measurement can completely describe the performance of a complex device such as a processor or a complete PC, benchmarks can be useful tools for comparing different components and systems.

However, the only truly accurate way to measure your system's performance is to test the system using the actual software applications you use. Although you think you might be testing one component of a system, often other parts of the system can have an effect.

It is inaccurate to compare systems with different processors, for example, if they also have different amounts or types of memory, different hard disks, video cards, and so on. All these things and more will skew the test results. Benchmarks can typically be divided into two types: component or system tests.

Component benchmarks measure the performance of specific parts of a computer system, such as a processor, hard disk, video card, or CD-ROM drive, whereas system benchmarks typically measure the performance of the entire computer system running a given application or test suite.

Benchmarks are, at most, only one kind of information you can use during the upgrading or purchasing process. You are best served by testing the system using your own set of software operating systems and applications and in the configuration you will be running.

Several companies specialize in benchmark tests and software. The following table lists the companies and the benchmarks they are known for. You can contact these companies via the information in the Vendor List on the DVD.

Company	Benchmarks Published	Benchmark Type
Futuremark (formerly MadOnion.com)	SysMark PCMark Pro 3DMark	System System 3D graphics
Lionbridge (Veritest)	Winstone	System
(PC Magazine benchmarks)	WinBench CD WinBench NetBench WebBench	System CD/DVD drives Network Web server
Business Applications Performance Corporation (BAPCo)	MobileMark	Notebook battery life
Standard Performance	SPECint	Processor Integer
Evaluation Corporation	SPECfp	Processor Floating-Point
SiSoftware	Sandra	System, memory, processor, multimedia