Putting it all in RAM (was: comparing CPU's)

[Lennart Sorensen]

On Mon, Aug 28, 2006 at 03:53:01PM -0400, ted leslie wrote:
> 2 x 2GB on one cpu
> 
> 2 x 2 GB on the other, and 2 x 512MB
> 
> oddly enough my current tyan (not the 16 slot one),
> has 4 slots for one cpu and 2 slots for the other, for a total of 6,
> a bit odd, but its not really a high end server board, more good
> workstation board.

I have seen Asus boards like that too.  They still recomended that for
optimal perforamnce, each channel have the same amount of ram, so for
example you could have 4 * 1GB on one cpu and 2 * 2GB on the other.  It
means if you started with 4 * 1GB in the system, you could upgrade by
moving that all to the cpu with 4 sockets, and putting two new 2GB
modules on the second cpu and still have it balanced.  Of course you are
not required to do this, and the extra 1 cycle latency to get to the
memory on the other cpu isn't really that big a deal for most users I
imagine.  As the NUMA support in linux gets better and better, it may
become a non issue, if the kernel simply recognizes that a program using
a lot of memory is better to place on the cpu that has the most memory
directly connected.  I don't think it is that smart yet though.

--
Len Sorensen
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