Will a New CPU Give Your PC More Vroom?
Kirk Steers
If you think you can feed your need for PC speed without investing in a whole new system, simply by replacing your old CPU with a newer and faster one, you're right--probably. A CPU upgrade can be a cost-effective way to boost PC performance, but it's not for everyone. Any prospective upgrader should ask two questions: How much performance will a new processor add to my PC? And is the bounce worth the cost?
You can find a CPU upgrade for almost any PC--from systems based on Intel's ancient 80486 chip through today's Pentium III models. But don't expect miracles from a new CPU if its clock speed is only slightly higher than that of your current CPU. A new processor running at twice the clock speed you're used to won't come close to doubling your system's performance. A 10 to 20 percent jump in performance is more realistic.
That's because other components play a big role in determining your system's overall performance. For example, dwindling hard disk space or too little RAM can slow down a system that's trying to process big spreadsheets or databases. And adding a topflight graphics card to your PC can dramatically improve the look and play of many games.
But if you're on a tight budget and you need a moderate, across-the-board performance boost, adding a new CPU can be worthwhile. Our rule of thumb: If you're staying in the same processor class, buy a CPU upgrade only if it will at least double your current clock speed--from 400 MHz to 800 MHz, for example. Better yet, move up an entire CPU class, such as from a Celeron chip to a full-fledged Pentium II or Pentium III.
If you have an older system, keep in mind that powerful new PCs are cheaper than ever. If a CPU upgrade costs more than $300, you may be better off spending a little more for a new PC.
Here's what you need to know about your PC before you buy a new CPU:
What's your old CPU's name? Use Intel's Processor Frequency ID Utility to identify the company's CPUs.
What's your PC's chip set? The chip set your motherboard uses determines what types of CPU, RAM, hard drive, and other hardware will work with your PC. To discover what chip set your PC uses, look in your system's manual or download and run a hardware diagnostic program such as the HWInfo shareware package.
Does it use a socket or a slot? The type of CPU connector your motherboard uses determines which CPUs can connect to your system. Figure 1 lists information to help you determine what your PC uses.
What about your frontside bus and multipliers? The frontside bus (or FSB) is the path between your RAM and CPU. It runs at a particular frequency: 66, 100, or 133 MHz. The motherboard multiplies that frequency to drive the CPU. For example, a Pentium II-233 CPU typically runs on a motherboard with a 66-MHz FSB and a multiplier of 3.5. The same system can run a Pentium II-266 CPU if you change the multiplier from 3.5 to 4. But running a Pentium II-400 CPU on that system would be a waste: With an FSB of 66 MHz and a top multiplier of 4, the old machine can run no faster than 266 MHz.
What is the voltage? If you're adding a standard CPU rather than an upgrade processor, make sure your motherboard's CPU voltage matches the voltage needs of your new CPU. Some motherboards support multiple CPU voltage settings, but many older boards don't. Check your manual to be sure of what you need.
Kirk Steers is a PC World contributing editor. Hardware Tips welcomes your tips and questions and pays $50 for published items.
More Zip for Your Zip
If you frequently use a removable storage drive--such as an Iomega Zip or Jaz drive--you can speed up data writing to the drive by enabling write-behind caching. This arrangement allows Windows to temporarily store data destined for the disk in RAM and then write it to the disk when no other tasks are being performed. To enable this option, launch Control Panel's System applet, select Performance, File System, Removable Disk, and check the Enable write-behind caching on all removable disk drives box.