Dave said:
I think I know exactly what the problem is. A thought occurred to
me, so I downloaded the manual for this motherboard to confirm it. Not
only does this mainboard support dual channel RAM, it apparently
requires it. It states at one point that dual channel can not be
enabled with only one stick of RAM installed (duh), so that would
imply that you can install one stick of ram. But then on the
configuration chart, it shows two sticks of RAM on the inside slots, two
sticks of RAM on the outside slots, or all four RAM slots occupied.
While the manual doesn't seem to state with absolute certainty that it
requires a minimum of two sticks of RAM, I'm betting this board will
not complete POST with just one stick. -Dave
From the Gigabyte manual
"Due to CPU limitations, read the following guidelines before installing
the memory in Dual Channel mode.
1. Dual Channel mode cannot be enabled if only one DDR2 memory module
is installed.
2. When enabling Dual Channel mode with two or four memory modules, it
is recommended that memory of the same capacity, brand, speed, and
chips be used and installed in the same colored DDR2 sockets for
optimum performance.
The #1 bullet item, does not go out of its way to discount operation with
a single stick. It says you can't use Dual Channel mode with just one stick.
As far as I'm aware, AMD processors have never prevented the possibility
of operation with one stick of RAM. The most restrictive processors (with
built-in memory controller), would only operate single channel mode, if
the DIMMs were placed in a particular channel. That stopped being an
issue, after revision D processors. So anything E or later is more flexible.
A revision D or earlier processor, could run with 1, 2, or 4 sticks.
A single channel config, using 1 or 2 sticks placed in the same channel,
would place the DIMMs on the least significant channel. If you stuck a single
stick on the upper channel, the board could not start. But that
issue stopped when revision E came out. (3 sticks could not work,
because of the "128 bit" nature of the AMD implementation at that time.
It required matched pairs, because the DIMMs operated in the same
mode, across from one another.)
Anything E or later, runs with 1,2,3, or four sticks, and is totally
flexible. Some configurations have better memory bandwidth than
others, but if you just blindly plug sticks into the machine,
it works.
The modern Phenom processors, support "ganged" or "unganged" operation.
That is a purposeful choice, to operating the memory channels independently.
That too implies, that if desired, a single stick can be used. You
can see some ganged versus unganged operations results here. Using
two sticks, and operating then unganged, would be recommended for
a slight boost in games. But because the channels can be operated
independently, you should be able to use a single stick.
http://ixbtlabs.com/articles3/cpu/amd-phenom-x4-9850-ganged-unganged-p1.html
As for "proof", there is proof on the AMD site. You can access the
series of "BIOS writer" documents, to find out about how the
various processors can be configured. But the documentation is
too hard to interpret, to be useful in settling arguments (mainly
because it addresses a whole bunch of processor types at the
same time, without naming them). I'm surprised any developer could
use their documentation, without being on the phone all day with
them to get clear answers. AMD could have helped out a lot, by
providing the equivalent of the "memory guides" that Intel provided
for some of their chipsets.
Paul
It seems to be fast enough