Is
the Power Supply Overlooked?...
When building a typical PC (or even our dream machine) we
often overlook a very important key component, the power
supply. Some hardware vendors take advantage of this
opportunity by saving costs and often fail to include a power
supply that is powerful enough for the needs of all the other
hardware in the system. It's a fact that power supplies can be
a cause of many possible problems in a PC. Erratic behavior
in the operating system, unstable memory, an unstable CPU,
issues with USB and Firewire devices, and random shutdowns are
just a few examples.
With all the advances of modern technology and smaller
components, you would think hat less power would be required.
Generally this is not true. With higher CPU speeds, and more
advanced graphics cards, the power requirements of even the
average PC have increased. And with more power comes more heat.
And with more heat comes the need for more cooling systems,
which in turn use more power. It's a viscous cycle! The standard
video card which used to come with a simple heat sink to cool its
processor now comes with a fan because the processor on the
video card runs so hot, the a heat sink alone isn't good enough.
In addition to drawing the heat away from the devices,
additional fans are required to draw cooler air in and heated
air out. More fans require more power.
Years ago we could easily operate with a 120-180 watt power
supply. By today's standards, this is way below the levels a PC
needs to function normally. Although it is called a power
supply, it does not really produce power at all. Instead it
transforms unfiltered high AC voltage to a regulated low DC
voltage. This process by itself creates heat which is why all
power supplies are equipped with fans themselves.
There are two methods to determining how much power you
actually need. The first is to simply purchase the highest rated
power supply you can afford (450-550W). The second, less costly
method is by approximating the computing component's use of
wattage based on the table below:
| Device
|
Power Consumption
|
| Accelerated Graphics Port card w/o Fan
|
35-50 W |
| Peripheral Component Interconnect (PCI) card
|
5-10 W |
| Floppy disk drive |
5 W |
| Network interface card
|
4 -8 W |
| 50X CD-ROM drive |
10-25 W |
| RAM 128M PC133 |
8-10 W |
| DDRAM 128 333 Mhz |
10-15 W |
| 5200 RPM (IDE) hard disk drive
|
8-12 W |
| 7200 RPM IDE hard disk drive
|
10-15 W |
| Motherboard (without CPU, RAM, Fan)
|
30-40 W |
| Intel 733 MHz Pentium III
|
23.5 W |
| AMD 600 MHz Athlon |
45 W |
| Intel 2Ghz Pentium 4 |
69-89 W |
| AMD Athlon XP 1900+ |
68 W |
| CPU Fan |
1-5 W |
| Case Fan |
2-10 W |
A final factor in determining the kind of power supply you
should select is future expansion. The best rule of thumb is to
add 25% to take this into account.
In your experience, you may have had a power supply that has
worked for many months or even years and then suddenly one day
your system goes nuts. Here are some common power supply related
failures you should look for:
1. Insufficient power supply
– this is normally the case as you upgrade or add load
to your system. Your system might work normally for quite some
time until you adding peripherals and expansion cards.
2. Overheating
– the efficiency of your power supply is degraded as the
temperature goes up. This is even worse if you are operating
above the normal room temperature.
3. Power surges or quality of
AC power – We have discussed power surge
protectors with our other tech tips. Also be aware of other
appliances that can interfere with the AC power line.
4. Insufficient airflow
– make sure you have ample space outside your power
supply and inside the computer case. It needs both clear
ventilation for air to flow through the power supply.
Occasionally check for dust accumulation at its grill guard. A
can of compressed air can usually remedy this problem easily.
We hope you've found this powerful (pardon the pun) tech tip
useful!
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