Every 7.8μs your computer’s memory has a hiccup

The text discusses an experiment conducted to observe the effects of dynamic RAM (DRAM) refresh cycles on software performance. It explains how DRAM stores data using tiny capacitors that gradually lose their charge, requiring periodic refreshes to maintain data integrity. The author uses a C program to measure memory load times and detect any noticeable delay caused by the refresh process. By applying Fast Fourier Transform (FFT) to the collected data, they identify a consistent frequency spike corresponding to the 64ms refresh interval. This experiment demonstrates that subtle hardware behaviors can be observed from simple userspace processes, which has implications for security vulnerabilities like Rowhammer and Meltdown/Spectre attacks.