Abit KX7-333/KX7-333R DDR Athlon
Last updated: 10/3/2002
QUALITY. Masking, wave
soldering, and the trace and ground plane layout are quite good.
The silk-screening on this board is fairly
good; however, it is not as good as the EpoX boards we have reviewed which
were rated excellent in this category. Labels are difficult to find
The DDR-SDRAM sockets are of very good quality
and have what appear to be gold-plated contacts (they are difficult to see).
I counted 48 105°C electrolytic capacitors.
The EpoX 8kHA+ with the VIA KT266A chipset had 53 (and audio). That is not
a really significant difference and is still a lot of capacitors for a motherboard.
processor core voltage regulator circuitry consisting primarily of 1) an Intersil
HIP6301 Multi-Phase Buck PWM Controller, 2) three Intersil HIP6601A gate drivers,
3) six Fairchild FDB6670 N-channel logic level PowerTrench MOSFETs, the large
electrolytic capacitors in the picture, and the four toroid coil inductors. At
a glance, it looks like it came right out of the Intersil spec sheets and app
notes and it compares well with the recommendations in the AMD
Voltage Regulation Design Application Note (PDF). The regulation
circuitry for the DDR memory, AGP interface and other chips use most of the
rest of the Electrolytics and employ Intersil controllers and regulators.
Going back to the picture, I can't say I like the metallic-looking (it's not
conductive when measured with an ohmmeter) piece of tape next to the CPU. I've
never seen anything like that before on a motherboard. Thinking it might
be a protective covering for an engineering change, I e-mailed Abit and asked
them what it was. The response was:
"I think you are talking about the Overclocking
Strips. They give a little more stability when tweaking your CPU."
Prodding them did not produce any more information. Maybe,
they can't explain how it works (if it does). Looking around the Internet
with a search engine turned-up more info/rumors. Apparently, Abit employees
used this as one of their tricks to overclock their own computers and Abit
merely included them in the manufacturing process. This makes them
engineering changes after the fact and a poor practice. They certainly
do not look like something one should see on a professionally-designed, quality
product. One might presume that the tape increases the capacitance
between traces it covers and distributes noise spikes/ringing on one of them
to the others, thus weakening them on all of them. That is not the
way I learned to decouple logic circuits.
There are two more pieces of tape on the bottom of the
motherboard. They are clear tape and may be just protecting the battery,
etc. from shorts. They don't look good either--band aids.
I do not overclock processors and do not recommend it,
having made that mistake several times in the past and suffering the consequences
of the corrupted personal and customer data that resulted. AMD
emphatically does not recommend it either. Doing it may void the
there have been a flurry of problems reported with the heatsink-fans that
motherboard manufacturer's have been installing on VIA Northbridge chips. Unscrewing
the fan from the heatsink and looking at the bottom reveals that the one
used for the KX7-333 is an ADDA ADO412MS-G70. The specifications
for the fan are at: http://www.addausa.com/specifications/dclist.pdf. The
mean-time-between-failures is not specified, but fans with sleeve bearings
usually have a specified lifespan of about 20,000 hours and single bearing,
ball bearing fans roughly twice that long. My experience with chipset
and CPU fans with sleeve bearings shows that you will be lucky if one doesn't
break within a year of average use. Furthermore, before they do break
they often expel bearing residue in the form of a fine black powder, which
seems to have an affinity for motherboards and is probably not too good
Passive cooling would be more reliable and
the chip/motherboard should be designed to make it possible. If fans
are used, they should be high quality and have ball bearings. If the
CPU is not overclocked, this motherboard will work without the fan. If
it breaks, simply unscrew the four screws holding the fan to the heatsink,
while holding the heatsink so it won't work loose, and unplug and discard
it. The heat sink is barely warm to the touch when the fan is removed
and the computer is working hard.
|10/6/02 Just three days after this
review was originally published, the Northbridge fan started making
that screeching noise one typically hears, when first turning on
the computer, that indicates the bearing is seizing and starting
to fail. Larry
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