Discuss the principles and challenges of designing high-speed memory interfaces such as DDR (Double Data Rate) SDRAM and GDDR (Graphics Double Data Rate) for modern computing and graphics applications.

High-speed memory interfaces like DDR and GDDR provide high-bandwidth data transfer between the CPU/GPU and system memory. Challenges include signal integrity, timing constraints, and power consumption. Techniques like data strobing, clock synchronization, and bus topology optimization are used to address these challenges.