Dual channel with Sonoma...

[Fox5]

If I get a Sonoma based laptop that has 512MB memory integrated into the laptop(nonremovable), can I just add another 512MB stick and get dual channel? How about a 1GB stick? Or does it still have to follow the same old 'same brand, same chips, same size' rule?

 

[Mingon]

I am not sure that the chipset with intergrated graphics can run dual channel. My laptop currently is runnning dual channel with 1gb and 1 256mb sticks. They are running at a reduced speed 400mhz rather than 533.

 

[Fox5]

Hmm, it would make sense if the chipset with integrated graphics could run dual channel, the integrated graphics could actually use the bandwidth boost.
So if you mismatch the sticks the speed will downclock?

 

[fbrdphreak]

It depends what chipset your laptop has. Intel has a 915GMS chipset (http://www.intel.com/products/chipsets/915GMS/index.htm) that only has a 400MHz FSB & single channel 400Mhz DDR2; on this obviously dual channel is not available.

All other Intel Pentium M chipsets with integrated graphics do support dual channel DDR2.

And yes, if your sticks are not compatible together you will not get dual channel. Theoretically integrated graphics should benefit due to the increased bandwidth, but this has not been quantifiably verified. I am working on an article investigating this very issue.

 

[Fox5]

Well, I just ordered an IBM X41 Tablet, I have no idea what chipset it uses, just that it's 915 something.
It uses a 400mhz fsb cpu, but ships with 533mhz memory integrated into the motherboard. I wonder what kind of ram I'd have to buy to get dual channel out of this...

Also, up above Mingon said that his laptop is running in dual channel with mismatched sticks, a 1GB stick alongside a 256MB stick, but the speed is reduced. It's not clear if they're reduced because one stick is only pc3200, or if because they're different size, or if it's a limitation of the platform. I've read similar stories about mismatching sticks where it'll run in dual channel and down clock, but nobody seems to be sure whether or not it's possible to have dual channel 533mhz.

Edit: It uses the 915GM chipset, just found that. Disappointing that it doesn't really support any of the features of said chipset though, just the graphics and memory bus it appears.

 

[fbrdphreak]

The 915GM supports DDR2 533 and 400MHz FSB, you'll have no problems there.

If you mix DDR2 400 (PC2-3200) with DDR2 533 (PC2-4200), the sticks will most likely run @ 400. This will also prevent it from running in DC mode of course.

Now if you mix a 1GB + 256MB DDR2 533, it will still run @ 533 but not in dual channel.

 

[Fox5]

Originally posted by: fbrdphreak
The 915GM supports DDR2 533 and 400MHz FSB, you'll have no problems there.

If you mix DDR2 400 (PC2-3200) with DDR2 533 (PC2-4200), the sticks will most likely run @ 400. This will also prevent it from running in DC mode of course.

Now if you mix a 1GB + 256MB DDR2 533, it will still run @ 533 but not in dual channel.

Hmm, people(like Mingon above) state that dual channel does work though, I guess 915 doesn't have nforce2ish dual channel support though.(nforce2 would work with almost any configuration, but only the platform used the extra memory and not the cpu)

Guess I'll have to buy another 512MB stick. Supposendly the IBM uses Hynix memory, though I'll check to make sure my particular one has that before I order the memory. What manufactuers use Hynix chips?

I'm really interested in seeing what kind of performance difference dual channel actually makes for the integrated graphics though, I know it has virtually no effect for cpu performance, but the GMA900 has specs that could use more bandwidth, and I doubt Intel has as smart a memory architecture on their chips as ATI and nvidia do on theirs. ATI's new XMA200 integrated graphics I think sees about a 20% performance boost with dual channel.

 

[fbrdphreak]

Well, if you give it a couple weeks I'll have an article out comparing Sonoma performance as well as GMA900 performance (DDR2 400 & 533, dual & single channel)

 

[Fox5]

Originally posted by: fbrdphreak
Well, if you give it a couple weeks I'll have an article out comparing Sonoma performance as well as GMA900 performance (DDR2 400 & 533, dual & single channel)

Cool, well I'll have a couple weeks to kill, my X41T isn't due to ship till August 1st.

BTW, I've seen plenty of reviews of the GMA900 that show it has abyssmal DirectX9 and OpenGL 2.0 performance, are you going to do any DX8/8.1 or OpenGL1.3/1.4 testing?(for instance, using the command line shortcuts in doom 3 and halflife 2 to lower the settings?)

 

[fbrdphreak]

Originally posted by: Fox5

Originally posted by: fbrdphreak
Well, if you give it a couple weeks I'll have an article out comparing Sonoma performance as well as GMA900 performance (DDR2 400 & 533, dual & single channel)

Cool, well I'll have a couple weeks to kill, my X41T isn't due to ship till August 1st.

BTW, I've seen plenty of reviews of the GMA900 that show it has abyssmal DirectX9 and OpenGL 2.0 performance, are you going to do any DX8/8.1 or OpenGL1.3/1.4 testing?(for instance, using the command line shortcuts in doom 3 and halflife 2 to lower the settings?)

Hmmmm that is a VERY good idea. Let me investigate this some more and I'll let you know. I should actually begin the GMA900 testing today or tomorrow.