CPU-z is claiming I am running dual

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bigbear2007 · #1 Post by **bigbear2007** » Wed Jan 24, 2007 7:38 pm

on 1x512M & 1x1G

Is it possible ?

#2 Post by **RonS** » Wed Jan 24, 2007 8:55 pm

bigbear2007 wrote:Is it possible ?

Nope.

#3 Post by **dr_st** » Thu Jan 25, 2007 1:47 am

Actually it is.

#4 Post by **rkawakami** » Thu Jan 25, 2007 1:53 am

ref: http://en.wikipedia.org/wiki/Dual-channel (which says "yes" it's possible)
http://www.intel.com/support/motherboar ... 011965.htm (which says "no"; note: this says desktops)

laundromatt · #5 Post by **laundromatt** » Thu Jan 25, 2007 3:43 am

so which is it?

Zeus · #6 Post by **Zeus** » Thu Jan 25, 2007 9:29 am

you are running dual; thinkpads can do it, somehow

brentpresley · #7 Post by **brentpresley** » Thu Jan 25, 2007 12:07 pm

Zeus wrote:you are running dual; thinkpads can do it, somehow

I would like to see some definitive proof for this.

FWIW, CPU-Z normally just looks to see if both DIMM slots are occupied in a dual capable system, and doesn't actually query the chipset to see if it is truly running in dual mode.

Download memtest86, burn it to a CD and boot from it. That program SHOULD be able to ID dual channel properly. (you want version 1.70)

#8 Post by **RonS** » Thu Jan 25, 2007 1:10 pm

I just downloaded and read some of Intel's datasheet for the 945PM, which includes the memory controller.

Three modes are supported:

1. Single channel.
2. Dual-channel symmetric. This is the fastest mode. Both memory modules must be the same size.
3. Dual-channel asymmetric. Performance is just slightly better than single-channel.

http://download.intel.com/design/mobile ... 921903.pdf see page 337

So, I stand corrected. Dual-channel is supported with mismatching memory modules, although in a mode that provides almost no performance boost over single-channel

brentpresley · #9 Post by **brentpresley** » Thu Jan 25, 2007 1:35 pm

RonS wrote:Dual-channel is supported with mismatching memory modules, although in a mode that provides almost no performance boost over single-channel

So why even call it Dual-Channel? It is effectively Single Channel w/ 2 dimms, right?

#10 Post by **RonS** » Thu Jan 25, 2007 1:59 pm

Based on my scant reading, dual-channel asymmetric mode gets you greater than single-channel performance only when software reads memory that alternates between the two modules, which Intel says is "unlikely."

#11 Post by **dr_st** » Thu Jan 25, 2007 5:13 pm

RonS wrote:So, I stand corrected. Dual-channel is supported with mismatching memory modules, although in a mode that provides almost no performance boost over single-channel

That's OK, any dual channel offers only marginal performance boost anyway.

I remember these discussions from about a year, a year and a half ago, when everyone was surprised to see that Dual Channel can be run with non-identical modules, because we were so used to desktop chipsets, where there is no such option.

CPU-z is claiming I am running dual

CPU-z is claiming I am running dual

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