Challenges and Future Directions for Computing Systems: Logic, Memory, and Interconnect

Rapid digital data creation is driving an unprecedented demand for computing power, but conventional scaling of the three core elements—logic, memory, and interconnect—has reached physical and economic limits, threatening the continued growth of silicon‑based systems.

The background section outlines how data‑driven applications (e.g., smart cities, autonomous vehicles) increase energy consumption, and explains that maintaining energy efficiency proportional to data growth is essential to avoid unsustainable power use.

In the logic domain, the article reviews CMOS scaling, the end of Moore's Law, multi‑core architectures, and the challenges of interconnect bandwidth, noting that faster transistors no longer translate into higher clock rates without incurring thermal and power penalties.

Memory scaling is constrained by reduced capacitance and leakage in DRAM and NAND; 3‑D stacking (HBM, V‑NAND) and emerging non‑volatile memories such as PRAM and RRAM are presented as promising solutions, though they introduce new design complexities for high‑performance interconnects.

Interconnect research shows a shift from traditional NRZ signaling to PAM‑4 to double bandwidth, but higher‑order PAM (e.g., PAM‑8, PAM‑16) suffers from SNR degradation, making it unsustainable. Optical interconnects, especially with dense‑wave‑division multiplexing, are identified as the long‑term answer for bandwidth‑limited electrical channels.

The conclusion emphasizes that specialized IC design, design reuse, and innovative interconnect architectures (e.g., forwarded‑clock, ADC/DSP‑based links) together with 3‑D integration and new memory devices provide viable paths for sustaining computing performance over the next decade.