Hi All,
I have a somewhat old computer which I use everyday. The CPU is an AMD
Duron 800Mhz. I'd like to upgrade to a faster CPU, preferably an Athlon.
The problem is that the motherboard manual does not state the maximum
supported CPU speed. It only says up to ~1.2Ghz or faster. I think this
is because when the motherboard was manufactured, 1.2Ghz was the
fastest AMD CPU available. How can I find out the maximum CPU speed my
motherboard can handle? The motherboard is a GA7ZM Micro ATX based on a
VIA Apollo VT 8363 KT133 chipset. Thanks!
There are three main factors, some of which we can resolve
now and some will take a test and monitoring.
1) The KT133 chipset only supports 100MHz/DDR200 FSB. This
limits the stock speed processors to those having 200
"System Bus (MHz)" as Gigabyte put it, but they should have
stated 100MHz/DDR200 as that would be more technically
correct. However, there is a chance you could still run
some newer processor with a faster spec'd FSB than DDR200,
running it essentially underclocked to it's stock multiplier
times the DDR200. For example if the CPU multiplier were
14X, on 100MHz FSB, the result is a processor running at
1.4GHz. Of course you could instead look for an old 1.4Ghz
T-Bird Athlon but they may be rarer today, and use more
power. There might also be CPU multiplier support issues, I
don't really recall all the details anymore and they also
varied per board so even if I guessed it might not be
applicable.
2) Power is a factor. The board might (probably does)
support the lower CPU vcore voltage of newer processors, but
these newer faster processors at lower voltage consume a
significant amount more current... possibly a fair bit more
than the motherboard designers intended, more than the
board's VRM CPU supply subcircuit was engineered to handle.
It may make the mosfets and capacitors run hot and being
aged capacitors already, they might have an unacceptibly
short life running hotter. If the increased heat is only
moderate one solution might be to install a small fan
blowing upon that area, or if your heatsink has a high
volume fan and is oriented such that a large % of the
exhaust flows over that area it might be sufficient already
to cool the VRM subcircuit.
Correction - your board's VRM subcircuit, based on the
picture on the page for the CPU support, looks a bit
compromised and relocated probably due to being a mATX board
and old enough that processors didnt use much current yet.
Much of it is placed on the other side of the memory and it
may not be very well cooled, and it looks as though
Gigabyte left a few capacitors off the board where they
might've been installed since at the time processors didn't
use as much current. I would be cautious even more about
the resultant heat of upgrading to the fastest processor the
board "might" be able to run.
3) Past the first Palomino, perhaps even just before that,
there were some signaling changes in the board circuitry and
a bios update "might" be needed for some processors. If you
can find no further info about your specific board then the
best attempt would be flashing to the latest bios first then
trying any CPU you had. If this upgrade requires purchasing
new processor and it isnt' very cheap, as another poster
mentioned it might now be time to look at replacing the
whole processor, board, and memory combo. Unfortunately it
is also likely you'd need a new PSU at this point as your
system used mostly 5V current while a modern one uses mostly
12V current, causing a change in the 5V vs 12V rail output
bias that PSUs were later designed to accomodate.
