Re: ram

["Peter A. H. Peterson" <pedro@tastytronic.net>]

Quoting Steffen Grunewald:
> Wouldn't this mean that, in a dual CPU system, one should better use
> 4 mem modules?

I just got an ASUS K8N-DL (because it is NUMA but fits into many ATX
cases). It is a strange board in that CPU2 has two slots and CPU1 has
4 slots. The slots are also named strangely. Here's a diagram:

| | [ ] 
| |     | | | |
| | [ ] | | | |
B A     | | | |
3 3     A A B B
        1 2 1 2

Two banks on the left, slot B3 and slot A3. Four banks on the right,
A1, A2, B1, and B2.

A table of says:

For CPU1		Sockets
Channel A		A1 and A2
Channel B		B1 and B2
For CPU2
Channel A		A3
Channel B		B3

This makes you think that if you have 4GB (4x1GB) you can put two
sticks in A3/B3 and two sticks in A1/A2.

But then you turn the page and you find this table:

"You may install 256M, 512M, 1G, 2G or 4G registered ECC DDR DIMMs
into the DIMM sockets using the memory configurations in this
section.

* For dual-channel configuration, the total size of memory modules
  installed per channel must be the same for better performance.
  Single CPU:
   A1 + A2 = B1 + B2
  Dual CPU:
   A1 + A2 = B1 + B2 = A3 + B3
* When using one DDR DIMM module, install into A1 slot only.
* When using two DDR DIMM modules, install into A1 and A2 slots only.
[snip]"

THe whole "A1 + A2 = B1 + B2 = A3 + B3" thing doesn't make sense
because it makes it sound like if you want dual-channel memory on both
CPUs you need RAM in all 6 slots, and each needs to be equal, which
seems extremely limiting.

I put two in A1/A2 and two in A3/B3... but then that means that
channel A has 3 GB and Channel B has 1GB.

Does anyone know what they're talking about, or has this board and has
done some testing?

I'm baffled.

pedro

-- 
Peter A. H. Peterson, technician and musician.
 ---=[ http://tastytronic.net/~pedro/ ]=---