I have just bought an extra 4Gb memory for my Abit AB9 Pro motherboard, I have plugged it in and it works fine (so I now have 6Gb) but I'm not convinced I understand the optimum way to install the memory.
There are four memory slots numbered 1, 2, 3 and 4, they are laid out as two pairs, 1 and 2 close together and 3 and 4 close together.
The manual is very ambiguous/confusing, it says:-
To reach the optimum performance in dual-channel configurations, install identical DDR2 DIMM pairs for each channel.
So does that mean a matched pair in both slots of channel A and a matched pair in both slots of channel B? That's not how the dealer had installed the existing memory and it isn't how their examples are either (see below).
It's pretty definite that Channel A is slot 1 and slot 2, Channel B is slot 3 and slot 4, that at least is clear enough. However this is where it gets confusing, the sample layouts are for "Dual Channel Asymmetric" and "Dual Channel Symmetric", it doesn't say which is the best and they don't make a lot of sense.
For example some "Dual Channel Asymmetric" layouts are:-
Slot1 256Mb, Slot2 256Mb, Slot3 512Mb, Slot4 512Mb Slot1 256Mb, Slot2 256Mb, Slot3 256Mb, Slot4 512Mb
Whereas a "Dual Channel Symmetric" examples are:-
Slot1 512Mb, Slot2 empty, Slot3 512Mb, Slot4 empty Slot1 256Mb, Slot2 256Mb, Slot3 empty, Slot4 512Mb Slot1 256Mb, Slot2 512Mb, Slot3 256Mb, Slot4 512Mb
Slots 1 and 3 are pink, slots 2 and 4 are red.
I *suspect* that I have it right, as follows:-
Slot1 1Gb, Slot2 2Gb, Slot3 1Gb, Slot4 2Gb
(the dealer installed 1Gb were already in slots 1 and 3)
but I'd really like to *know* that I have it right!
Right....
The slots close together represent one channel, There are supposedly some performance differences between running dual channel symmetric (where the amount of memory and memory type is identical in Channel A and B, but not necessarily the same size modules) and asymmetric (where you have modules that add up to a difference size, but same type in channel B) with favour to symmetric.
But really all that matters is that if you are using only two slots then the memory should be split between channels A and B and if you have a mix of modules (like you) then if possible you should give the same amount of memory to channel A and B.
Therefore your current configuration is as close to optimum as you are going to get with your modules.
On Wed, 2007-11-14 at 22:54 +0000, Chris G wrote:
I have just bought an extra 4Gb memory for my Abit AB9 Pro motherboard, I have plugged it in and it works fine (so I now have 6Gb) but I'm not convinced I understand the optimum way to install the memory.
There are four memory slots numbered 1, 2, 3 and 4, they are laid out as two pairs, 1 and 2 close together and 3 and 4 close together.
The manual is very ambiguous/confusing, it says:-
To reach the optimum performance in dual-channel configurations, install identical DDR2 DIMM pairs for each channel.So does that mean a matched pair in both slots of channel A and a matched pair in both slots of channel B? That's not how the dealer had installed the existing memory and it isn't how their examples are either (see below).
It's pretty definite that Channel A is slot 1 and slot 2, Channel B is slot 3 and slot 4, that at least is clear enough. However this is where it gets confusing, the sample layouts are for "Dual Channel Asymmetric" and "Dual Channel Symmetric", it doesn't say which is the best and they don't make a lot of sense.
For example some "Dual Channel Asymmetric" layouts are:-
Slot1 256Mb, Slot2 256Mb, Slot3 512Mb, Slot4 512Mb Slot1 256Mb, Slot2 256Mb, Slot3 256Mb, Slot4 512Mb
Whereas a "Dual Channel Symmetric" examples are:-
Slot1 512Mb, Slot2 empty, Slot3 512Mb, Slot4 empty Slot1 256Mb, Slot2 256Mb, Slot3 empty, Slot4 512Mb Slot1 256Mb, Slot2 512Mb, Slot3 256Mb, Slot4 512Mb
Slots 1 and 3 are pink, slots 2 and 4 are red.
I *suspect* that I have it right, as follows:-
Slot1 1Gb, Slot2 2Gb, Slot3 1Gb, Slot4 2Gb
(the dealer installed 1Gb were already in slots 1 and 3)
but I'd really like to *know* that I have it right!
On Wed, Nov 14, 2007 at 11:51:06PM +0000, Wayne Stallwood wrote:
Right....
The slots close together represent one channel, There are supposedly some performance differences between running dual channel symmetric (where the amount of memory and memory type is identical in Channel A and B, but not necessarily the same size modules) and asymmetric (where you have modules that add up to a difference size, but same type in channel B) with favour to symmetric.
But really all that matters is that if you are using only two slots then the memory should be split between channels A and B and if you have a mix of modules (like you) then if possible you should give the same amount of memory to channel A and B.
Therefore your current configuration is as close to optimum as you are going to get with your modules.
OK, thanks very much for the outline, it's clarified what the manual obfuscated - and means I've got it about right! :-)
On Wed, 2007-11-14 at 22:54 +0000, Chris G wrote:
I have just bought an extra 4Gb memory for my Abit AB9 Pro motherboard, I have plugged it in and it works fine (so I now have 6Gb) but I'm not convinced I understand the optimum way to install the memory.
There are four memory slots numbered 1, 2, 3 and 4, they are laid out as two pairs, 1 and 2 close together and 3 and 4 close together.
The manual is very ambiguous/confusing, it says:-
To reach the optimum performance in dual-channel configurations, install identical DDR2 DIMM pairs for each channel.So does that mean a matched pair in both slots of channel A and a matched pair in both slots of channel B? That's not how the dealer had installed the existing memory and it isn't how their examples are either (see below).
It's pretty definite that Channel A is slot 1 and slot 2, Channel B is slot 3 and slot 4, that at least is clear enough. However this is where it gets confusing, the sample layouts are for "Dual Channel Asymmetric" and "Dual Channel Symmetric", it doesn't say which is the best and they don't make a lot of sense.
For example some "Dual Channel Asymmetric" layouts are:-
Slot1 256Mb, Slot2 256Mb, Slot3 512Mb, Slot4 512Mb Slot1 256Mb, Slot2 256Mb, Slot3 256Mb, Slot4 512Mb
Whereas a "Dual Channel Symmetric" examples are:-
Slot1 512Mb, Slot2 empty, Slot3 512Mb, Slot4 empty Slot1 256Mb, Slot2 256Mb, Slot3 empty, Slot4 512Mb Slot1 256Mb, Slot2 512Mb, Slot3 256Mb, Slot4 512Mb
Slots 1 and 3 are pink, slots 2 and 4 are red.
I *suspect* that I have it right, as follows:-
Slot1 1Gb, Slot2 2Gb, Slot3 1Gb, Slot4 2Gb
(the dealer installed 1Gb were already in slots 1 and 3)
but I'd really like to *know* that I have it right!
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Chris G -
Wayne Stallwood