What is the difference between shared single channel memory and shared dual channel memory?

Answer 1

Dual Channel is a mode where the memory can be used twice as fast.

Example: Two different computers, both have 1GB of memory. Computer A has a single stick of 1024MB of memory, while Computer B has two sticks of 512MB of memory. Computer B would (assuming the motherboard supports it, and nearly all do) be able to run in dual channel mode because the computer could access both sticks of memory at the same time. This would make Computer B perform slightly better than Computer A because there is only one channel available for that single stick of 1024MB of memory.

Shared memory, in either case, means a portion of the memory has been set aside for graphics processing. This occurs in computers (typically laptops and lower-end desktops) that do not have their own dedicated video card.

Answer 2

twin channel is quicker because there are 2 memory sticks sharing the workload. The sticks could be same (same speed, producer, length, and timings) and put in contained in the twin channel slots on the motherboard. There are in many cases 4 slots for the memory and the twin channel slots will be a diverse colour.