https://www.techpowerup.com/253929/intel-ice-lake-gpu-docs-reveal-unganged-memory-mode
 
When reading through the Gen11 GT2 whitepaper by Intel, which describes their upcoming integrated graphics architecture, we may have found a groundbreaking piece of information that concerns the memory architecture of computers running 10 nm "Ice Lake" processors. The whitepaper mentions the chip to feature a 4x32-bit LPDDR4/DDR4 interface as opposed to the 2x64-bit LPDDR4/DDR4 interface of current-generation chips such as "Coffee Lake." This is strong evidence that Intel's new architecture will have unganged dual-channel memory controllers (2x 64-bit), as opposed to the monolithic 128-bit IMC found on current-generation chips.
 
An unganged dual-channel memory interface consists of two independent memory controllers, each handling a 64-bit wide memory channel. This approach lets the processor execute two operations in tandem, given the accesses go to distinct memory banks. On top of that it's now possible to read and write at the same time, something that's can't be done in 128-bit memory mode. Unganged mode can shine when multiple (or multi-threaded) applications work with vast amounts of memory, which increases the likelihood that two independent banks of memory get accessed.