On Tue, Feb 11, 2014 at 3:35 PM, Joel Rees <joel.rees@gmail.com> wrote:
On Tue, Feb 11, 2014 at 1:58 PM, Gary Dale <garydale@torfree.net> wrote:
[...]
Your suggestion that it is the 8G + 1x4G which is being recognized
Not quite what I was trying to suggest. I was oversimplifying significantly.
And, now that I've been out for a walk, to see my wife's mom, it
occurs to me that the more likely scenario is the one that I think
others have implicitly assumed.
That is, that there is enough logic for the controller to *recognize*
the 8G stick, but not enough to fully *decode* it. Particularly, if
your compatibility table doesn't mention 8G, there would be no
surprise if the motherboard were able to see that it's an 8G stick and
decode just half of it. And if that's the case, getting a mate to the
8 you have would leave you able to read the lower half (or maybe the
upper half) of both 8G sticks, so you'd be able to access 16G, but not
24.
And I can think of a particular decoding arrangement where an 8G stick
all by itself could be fully decoded, but when you add more in the
second pair of slots there wouldn't be enough decode circuitry to
fully map both pairs of slots.
Thus the need to use a full set of diagnostics tests if you really
want to see what's happening.