Does the X220 utilize dual channel RAM?

I've noticed that CPU-z does not show anything indicating the motherboard utilizes dual channels. It could be the software needs an update for newer mobile sandy bridge processors or this chipset simply doesn't care.

The reason I ask is because I have a 2GB chip laying around and was wondering if it's worth coupling it with my 4GB chip which has the same speed and specs.

 

If the speed is different it will just clock down the 'faster' binned chip to the 'slower' binned chips speed.

sandy bridge can take up to 1866mhz ram if you interested in performance.

 

That does seem to be a little bug in the current (1.57) CPU-z. I've got 2 x 2GB in my T420s but dual channel is not mentioned. If the RAM modules have different capacities then the system will run in pseudo dual channel. I've not figured out how that works, but it gives most of the performance improvement of full dual channel.

SiSoftware Sandra has a good memory bandwidth benchmark. It reports about 16GB/s for my T420s.

John

 

I took your advice and ran Sandra to compare memory bandwidth between 1x4GB chip vs 1x4GB + 1x2GB chip to look for changes in bandwidth. Both chips have the same specs with the only difference being size.

With only 1 4GB module, bandwidth is 9 GB/s
With the 4GB and 2GB module, bandwidth is 14.6 GB/s

So it does seem that having 2 chips of identical size isn't necessary for dual channels, however, I'd hypothesize that having 2x4GB chips would better saturate the channels and probably up the bandwidth by about 1 more GB/s.

But 1 GB/s seems a bit insignificant, and hardly the perfomance hit I was expecting. I feel much better off using my 2GB chip that I bought for $23 and upping my RAM to 6GB, instead of trying to sell it for a few bucks and purchasing a 4GB chip.

And for what it's worth, my WEI score for memory went from 5.9 to 7.5.