[ALUG] Motherboard memory problem

[Chris G]

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 Green