No dual-channel mem on t400?

because it's DDR3?

 

I have 1g+2g ddr3 on my t400, in Everest u50 it shows "dual channel 128bit".So once you plug in 2 sticks same frequency ddr3 memory no matter they were different in size or manufacturer dual channel works for you.

 

I believe for dual channel it has to be 2 sticks of equal size even with DDR3. The Lenovo rep confirmed this. Try CPU-Z and see what it says yn1997. You can download it at www.cpuid.com

 

Cpuz cant even recognize ddr3 ram. And intel's dual channel is using different theory other than amd's, dont have to be equal size.

 

Crucial memory said t400 doesn't support dual channel mem...

 

With DDR3 speed matching the system bus speed, does dual channel even matter? I could see it being an issue with other laptops like Dell and Sony that use DDR2 at 800Mhz.

 

That's a good answer. I may need to review the purpose of dual channels...

 

Dual Channel has nothing to do with the FSB.
With Dual-Channel, bandwidth improves by about 10-15%, but the memory bandwidth is otherwise limited/bottlenecked by the FSB bandwidth.
Dual Channel works with different RAM sizes (1+2 GB) or (3+0.5 GB).
For more info on this, Read the Dual Channel RAM Guide. (It was basically compiled during the DDR2 era, but applies almost the same for DDR3 as well.)

Crucial -> Crap

 

That's what I said in not so many words. Even though the memory controller has double the bandwidth to the memory, the memory controller itself is limited by the system bus. So again, does it even matter?

 

I read something on Intel's site. It's a new technology that enables dual-channel even the size of the ram sticks is different. Can't remember the url now, but it definitely is a new feature available to T400/500

 

It's not new to T400/500 and Montevina, they have this technology even with Santa Rosa, it's called "Flex Mode". Check out the thread Andy posted.

But with the modern Intel chipset, single vs. dual won't give you a dramatic difference, it matters to AMD chipset more though.

 

I agree with you. In the past we did need 'dual channel' because the bus of CPU was often faster than that of RAM. However, in T400, since these two buses are both equal to 1066MHz, 'dual channel' will no longer boost the system's performance anymore.