Hey Newsgroup,
I got a minor problem, installing some more RAMs onto my new PC.
The base configuration was:
Two bricks DDR PC400 (512MB) in the first two slots of my abit av8.
Then I bought another brick (1GB) which would refuse working (code D.4.
which I cannot find in any manual) and some annoying beeping when set
in the 3rd block.
I tested some configurations:
--1---2---3---4--
-512-512-000-000- Okay
-512-512-1GB-000- Not okay
-512-000-1GB-000- Okay
-1GB-000-000-000- Okay
-512-000-512-000- Okay
Could it be that there has to be some symmetry in the RAM installation?
The manual says very few about that.
thanks
Thorben
The Abit AV8 is socket 939.
http://www.a1-electronics.net/AMD_Section/Mobos/939/Abit_AV8_Sept04.shtml
Be aware that there are differences in the AMD processors for S939.
The memory controller on Revision E processors, is better than any
previous revisions.
For processors before Revision E, then valid configurations involve
one, two, or four sticks of RAM. You cannot use three sticks of RAM
with a pre Rev.E processor. (Not without one or more sticks being
disabled by the BIOS, or the BIOS beeping a memory error.)
For your processor, two of the memory slots are on the "primary bus".
You can place one or two sticks in the primary slots. Documentation
for some motherboards might refer to slots B1, B2 as the primary
bus. If you install in single channel configuration in A1 and/or
A2, that won't work.
If you want dual channel, the sticks have to be matched in pairs,
and installed in the correct slots. A pair goes to the A1,B1 and
a pair goes in A2,B2. In other words, they have to occupy the same
relative slot level (A1, B1 are slot 1 decode on each bus).
So, the valid configs for a pre Revision E processor look like this.
You will have to match this table, to the one in your manual, to
get the correct labelling for your motherboard. But the fill pattern
for pre revision E processors looks like this. This table shows
all possible valid configs.
A1 A2 B1 B2
x x x 512MB Single channel mode (primary bus B1,B2)
x x 512MB x Single channel mode (primary bus B1,B2)
x x 512MB 256MB Single (sticks don't have to match)
512MB x 512MB x Matched pair A1,B1 dual channel
x 512MB x 512MB Matched pair A2,B2 dual channel
256MB 512MB 256MB 512MB Illustrates two matched pairs, dual ch.
With a revision E processor, like E3 or E6 etc., then the primary
bus distinction is eliminated in those processors. You can use any
slot for single channel mode, including using three DIMMs for single
channel. I'm not going to show all possible permutations and combinations,
but this shows that on a Revision E processor, any slot can be used
in a single channel mode. This table adds to the previous table,
but only applies to a Revision E processor or later.
A1 A2 B1 B2
x x x 512MB Single channel mode
x x 512MB x Single channel mode
x 512MB x x Single channel mode
512MB x x x Single channel mode
512MB 256MB 128MB x 896MB, single channel
So chances are, you have the wrong kind of processor for
just any old memory config. A new S939 processor of the
Revision E variety, will allow any number of slots to
be filled (but only some configs give high performance -
dual channel has more bandwidth than single channel).
A pre Revision E processor is not as flexible.
HTH,
Paul
