Hardware Reference
In-Depth Information
“The FCC does NOT currently authorize motherboards, cases, and internal power
supplies. Vendor claims that they are selling 'FCC-certified cases,' 'FCC-certified
motherboards,' or 'FCC-certified internal power supplies' are false.”
In fact, an FCC certification can be issued collectively only to a base unit consisting of
a computer case, motherboard, and power supply. Thus, a power supply purported to be
FCC-certified was actually certified along with a particular case and motherboard—not
necessarily the same case and motherboard you are using in your system. This does not
mean, however, that the manufacturer is being deceitful or that the power supply is in-
ferior. If anything, this means that when evaluating power supplies, you should place less
weight on the FCC certification than on other factors, such as UL certification.
Power-Use Calculations
When expanding or upgrading your PC, ensure that your power supply is capable of
providing sufficient current to power all the system's internal devices. One way to see
whether your system is capable of expansion is to calculate the levels of power consump-
tionbythevarioussystemcomponentsinyoursystem,andthencomparethattotherating
on the power supply to see if it is up to the job. This calculation can also help you decide
whether you must upgrade the power supply to a more capable unit. Unfortunately, these
calculations can be difficult to make accurately because many manufacturers do not pub-
lish detailed power consumption data for their products. In some cases, you can find the
specs from a similar component and go by that data instead. Usually components of the
same basic design, capability, and vintage have relatively the same power consumption
characteristics.
Table 18.26
shows the range of power usage for typical PC components
I've observed over the past few years.
Table 18.26 Power Consumption Calculation
