P4G8X Dual Channel Memory configuration

[moe]

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

If I fill all four DIMM memory sockets would the following configuration be
legal for dual channel operation or do all four memory boards have to be
identical?

Dimm A1 Dimm B1 Dimm A2 Dimm B2
512Meg 256Meg 512Meg 256Meg

From the explanation in the manual it's clear that the memory in
each channel DIMM A1/A2 and DIMM B1/B2 must be identical,
but it's not clear to me if both channels have to be identical.

Any input will be appreciated.

moe

 

[Paul]

Archived from groups: alt.comp.periphs.mainboard.asus (More info?)

In article <amebh0lh9k5cglmgg6sd4ifu0bk16q2bps@4ax.com>, moe @mci.com wrote:

> If I fill all four DIMM memory sockets would the following configuration be
> legal for dual channel operation or do all four memory boards have to be
> identical?
>
> Dimm A1 Dimm B1 Dimm A2 Dimm B2
> 512Meg 256Meg 512Meg 256Meg
>
> From the explanation in the manual it's clear that the memory in
> each channel DIMM A1/A2 and DIMM B1/B2 must be identical,
> but it's not clear to me if both channels have to be identical.
>
> Any input will be appreciated.
>
> moe

From the Intel E7205 datasheet (this is the one I have bookmarked):
http://www.intel.com/design/chipsets/e7205/datashts/25193702.pdf

Page 139

"Memory Operation
The MCH contains a dual channel DDR interface, with each channel
having 64 data bits and 8 ECC bits. The memory interface operates
in ³lock-step² with each other...

The memory must be populated in identical DIMM configurations
(i.e., Slot 0 of channel A must contain the same configuration DIMM
as Slot 0 of channel B). The configuration consists of the same
number of rows (1 or 2), the same technology part (128 Mb, 256 Mb,
512 Mb), the same DRAM chip width (x8, or x16), and the same speed."

so I think that means A1=B1 and A2=B2, not as you have shown. The
A1=B1 and A2=B2 is all the matching you need, so a pair of 512 and
a pair of 256 should work.

This info is also in the manual, section 2.5.2
http://www.asus.com/pub/ASUS/mb/sock478/p4g8x/e1133_p4g8x.pdf

Mushkin has some tips in their mainboard qualification section
for the P4G8X. Some of the info in there is probably old by
now, but may come in handy if you are having problems with the
board. There is a link off their front page to the mainboard
qualification section.

Paul