What processor technology introduce quad channels where the processor can access four dimms at the same time?

It is known as the Sandy Bridge. Sandy Bridge is the codename for a microarchitecture created by Intel starting in 2005 for focal preparing units in PCs to supplant the Nehalem microarchitecture. Intel showed a Sandy Bridge processor in 2009 and discharged first items in view of the engineering in January 2011 under the Core mark.

The answer is length!