Once you’ve done everything possible to optimize the operating system environment, if you find your system is still too slow, it’s time to consider hardware upgrades.

Add more RAM
The first hardware component to check is the amount of RAM, or main system memory, that is installed. For a machine running Windows 95 or 98, increasing memory to 64 MB will give you the best possible performance. In this environment, more than 64 MB usually won’t improve performance and in some cases can actually slow the system down.

If the computer in question is running Windows NT or Windows 2000, there is no upper limit to the amount of RAM that will improve performance. If the motherboard will accommodate 512 MB or more, for example, you can keep making it run faster by adding more RAM.

On the other hand, PCs running Windows 3.x and MS-DOS will rarely benefit from more than 16 MB of RAM. More won’t hurt, but it usually won’t make the system run any faster either, so there’s probably no point in spending any more money on RAM for computers that are operating in this environment.

Change RAM type or speed
Another change to consider is the type of memory the computer is using. If it presently has fast page-mode (FPM) RAM installed, you may want to investigate the feasibility of upgrading that to extended data out (EDO) RAM or even synchronous dynamic RAM (SDRAM) if your motherboard and BIOS support these faster memory technologies.

Even if you can’t change the type of memory, you may be able to upgrade to faster modules of the same type. Going from 70-nanosecond memory to 60-nanoseconds, for instance, will give you roughly a 15% performance boost. The key to changing memory speed is to be sure that all the modules in the system are the same speed and adjust the BIOS memory settings to reflect any substitutions you make.

Time for a new CPU
After you’ve done everything you can with memory, and system performance still needs to be improved, the next upgrade to consider is the CPU, also known as the processor, such as an Intel Pentium or AMD Athlon.

The first decision you need to make is whether a processor upgrade is practical for the system in question. The key to this decision hinges on two factors: What is the speed of the processor that is presently installed in the system, and what is the maximum speed the motherboard and BIOS will allow?

A useful rule of thumb here is that if you can’t double the processor speed, then a CPU upgrade probably isn’t a cost-effective option. The reason for this guideline is that processor speed alone is only one of the factors in determining overall system performance.

Voltage, clock speed, and multipliers
There are several ways to determine the upper limit of CPU speed your motherboard will support. The motherboard documentation is the best starting point, but most boards will have the information you need printed right on them.

Typically, you’ll find three sets of jumpers and/or DIP switches you will need to change when you install a new processor. One set specifies the voltage required by the processor; another designates the system bus speed; and the third sets the CPU clock ratio, or multiplier, to derive the processor speed.

Figure A illustrates a typical set of jumpers for CPU core voltage. This particular motherboard uses jumper blocks designated VR1 and VR2 to choose the appropriate voltage, ranging from 3.6 volts down to 2.5 volts. The legend in the table also shows which specific processors require the various voltage settings.

Figure A
Jumper options used to specify CPU voltage are clearly labeled on this motherboard.

Figure B illustrates a typical set of jumpers used to change bus speed. This particular motherboard uses jumper blocks designated CLK3, CLK2, and CLK1 to set the desired speed, ranging from 50 to 66 MHz. In this example, connecting CLK3 and CLK2 jumpers to pins 2-3 and CLK1 jumpers to pins 1-2 generates a bus speed of 60 MHz.

Figure B
By varying three sets of jumpers, this motherboard’s bus speed can be set to 50, 55, 60, and 66 MHz.

Figure C depicts a typical set of jumpers used to set the CPU clock speed multiplier. This motherboard uses jumper blocks designated FREQ1 and FREQ2 to set the multiplier that determines the processor speed. The available options on this board are multipliers of 1.5, 2, 2.5, and 3. In this example, FREQ1 connects pins 2-3 and FREQ2 connects pins 1-2, resulting in a multiplier of 2.0. Combined with the bus speed of 60 MHz as shown in Figure B, this motherboard is set to handle a 120-MHz CPU (60 MHz x 2.0 = 120 MHz).

Figure C
By varying the jumpers at FREQ1 and FREQ2, this motherboard’s clock speed can be multiplied by a factor of 1.5, 2, 2.5, or 3.

Your mobo’s max supported CPU
If you don’t know the maximum processor speed your motherboard will support, it’s easy to calculate. All you need to do is see what the highest bus speed is that you can set on the board and the highest ratio or multiplier. Multiply these two numbers, and that’s the fastest CPU speed the motherboard can be set to handle. The motherboard used in these examples has a maximum speed of 200 MHz (66 MHz bus x 3.0 CPU rate).

The actual bus speed represented as 66 MHz is 66.667, and if your board has a choice of 83 MHz, it represents 83.333. Using these numbers, the calculated CPU speed comes up to nice even multiples, such as 200 or 250 MHz.

The motherboard shown in this Daily Feature uses a Socket 7 processor form factor. Currently, the only Socket 7 processor available from Intel is the 233-MHz Pentium with MMX instructions. Even though this board does not have a setting for 233 MHz, there is no problem running a CPU at less than its rated speed. So in this case, if you wanted to upgrade the 120-MHz processor to a new, faster chip, you could run the 233 CPU at 200 MHz.

Avoid overclocking
On the other hand, you want to be careful not to set the board to a higher speed than the CPU is rated to handle. Such overclocking could result in higher performance, but the processor could also perform unreliably and even be damaged by such a setting. You overclock a processor at your own risk.

Jumperless motherboards
Some motherboards you may encounter don’t have jumpers or DIP switches to allow you to set the processor speed. Instead, they automatically detect the CPU type and set the bus speed and ratio accordingly. Such jumperless motherboards simplify the processor upgrade procedure and protect you from inadvertently trying to make the CPU run faster than its rated speed. On the other hand, these boards give you less control over processor speed and provide less visibility of the settings that are in effect. They also make it more difficult for you to determine the maximum processor speed the board will support.

A few simple hardware upgrades can speed your operating system. Start with RAM, but if you are using a legacy Microsoft OS, realize that sometimes more isn’t faster. Next, get the fastest CPU your motherboard supports. If you conclude that a processor upgrade is not a practical option for your existing motherboard, the only remaining avenue to improved performance is to replace the motherboard itself. I covered that procedure in “Replacing your motherboard: Which form factor is best?
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