Hardware Reference
In-Depth Information
a requirement that the power supply has active PFC. The main benefit of PFC supplies is that they do
not overheat building wiring or distort the AC source waveform, which causes less interference on
the line for other devices.
SLI-Ready and CrossFireX Certifications
Both NVIDIA and AMD have certification programs that test and certify power supplies to be able to
power systems with multiple graphics cards in either a Scalable Link Interface (SLI) or a CrossFire
configuration. This type of configuration puts extreme demands on the PSU, because it has to power
not only what would normally be a high-end motherboard, CPU, and multiple drives in a RAID
configuration, but also up to three video cards, which may be capable of drawing 300 watts or more
each.
The certification process involves PSU manufacturers sending PSUs in for testing, whereby they are
verified to supply sufficient power (and the proper type and number of connectors) to run the desired
graphics hardware as well as the system. Power supplies that have passed either of these
certifications are virtually guaranteed to produce high output and use high-quality design, engineering,
and manufacturing. For more information on these certifications, as well as lists of certified PSUs,
visit the following links:
•
Certified SLI-Ready Power Supplies
—
www.geforce.com/hardware/technology/sli
•
CrossFire Certified Power Supplies
—
http://support.amd.com/us/certified/power-supplies
I recommend checking the lists or looking for the “NVIDIA SLI-Ready” or “AMD CrossFireX
Technology” logos (see
Figures 18.37
and
18.38
)
on a power supply as an excellent indicator of a
high-power, high-quality unit.
Figure 18.37. NVIDIA SLI-Ready logo.
Figure 18.38. AMD CrossFireX Technology logo.
Safety Certifications
Many agencies around the world certify electric and electronic components for safety and quality.
The most commonly known agency in the United States is Underwriters Laboratories, Inc. (UL). UL
standard #60950—
Safety of Information Technology Equipment
—covers power supplies and other
PC components. You should always purchase power supplies and other devices that are UL-certified.
It has often been said that, although not every good product is UL-certified, no bad products are.
