A
t Maximum PC we typically review high-end, or “perfor-
mance,” monitors. These are the screens with the best
specs and thus most likely to meet the rigorous demands
of power users. But a recent spate of inexpensive 22-inch screens
had me wondering whether it’s worth trading some screen quality
in favor of price and size, both valuable commodities.
All three of the 22-inch LCDs I review on page 68 feature 6-bit
color as opposed to 8-bit color. The reason is cost. Even though all
desktop LCDs employ thin-film transistor (TFT) technology, there
are many variants of TFT. Of these, twisted nematic (TN) is the
cheapest to produce, so many vendors use it for their mass-market
models, e.g., these 22-inch LCDs. The trade-off is that TN panels
are incapable of 8-bit color.
Does this matter? Strictly speaking, 6-bit yields a total of
262,144 colors while 8-bit is capable of a whopping 16.7 million
colors. While this suggests a huge difference in appearance—and
one that would definitely be undesirable—it’s not quite as simple
as that. To bridge the color gap, vendors use compensation tech-
niques: either dithering, which combines adjacent pixels to simu-late a desired shade, or more commonly, frame rate control (FRC),
which rapidly cycles the 6-bit pixels to simulate the shades you
get natively from an 8-bit panel. Or at least most of the shades—
16,194,277, to be exact.
Overall, I found the three LCDs to be less rich and vibrant
than our favorite 8-bit panels—for instance the blue and green
in XP’s Bliss desktop appeared washed out—and vertical off-
axis was kind of weak (a characteristic of TN displays). But I
didn’t notice any visual artifacts, such as a loss of subtle detail
or apparent dithering. Indeed, I found the LCDs performed well
within the realm of acceptability for displays of this price, even if
their pictures weren’t eye-popping.Would you give up a couple bits per color if it
could save you some cash?64 MAXIMUMPC june 2007
in the lab Real-WoRld testing: Results. analysis. Recommendations
We’re big fans of Dell’s large 8-bit LCDs, but the company’s 6-bit
E228WFP is a tougher sell.KATHERINE STEVENSON
Examines the
Difference Between
6-bit and 8-bit LCDs
F
ire up your favorite temperature-monitoring program on a Core
2 processor and I’ll bet the reading you get is wrong. At least
that’s the conclusion I’ve come to after a confusing week of trying
to figure out which temp utility is accurate.
RightMark CPU Clock Utility (http://cpu.rightmark.org) tells me
that my lightly overclocked Core 2 Extreme QX6600 is idling at
32 C, yet Core Temp (http://tinyurl.com/2pkq4r) tells me it’s at 48 C.
Which one is right? Neither.
There are two different temperature measurements going on
inside a Core 2. Each individual core has its own digital thermalsensor (DTS) that writes a value to a register in the core. The num-
ber the DTS reports, however, is not the temperature of the core,
it is a value that counts down to zero. When it hits zero, the core
should throttle down. It’s also intended to be used for controlling
fan speeds, not as a direct temperature reference. Core Temp is
guessing (incorrectly, according to Intel) what the offset is.
There’s also an old-fashioned thermal diode inside the CPU,
just off to the side of the two processors, under the lid. Intel says
the temperature the diode reports is probably more indicative of
the CPU’s actual temperature (and it’s probably what the BIOS
and most OEM motherboard utilities report). Still, that number isn’t
necessarily correct.
Believe it or not, to accurately measure the temperature of a
Core 2 chip, Intel recommends that you mill out a groove in the
heat spreader and install a thermal couple at the exact center of
the heat spreader. If I did this, I would probably see that the CPU
is nowhere near the maximum temperature—65 C—that Intel rates
it for. The moral of this story? Take your temp utility readings with
a grain of salt.Gordon Mah Ung
Takes His Quad’s Temperature
And wonders why the hell you can’t get an
accurate temperature from a Core 2 chip