That clock rate is the headline: it delivers the read-write bandwidth needed in high-performance networking gear, packet processors, and compute accelerators where every nanosecond of memory access latency matters. The memory is organized as 4M x 18 bits, accessed through a parallel interface, and operates from a 1.26V to 1.34V supply rail. QDR IV stands for Quad Data Rate, fourth generation — it transfers four words per clock cycle (two reads and two writes), effectively quadrupling the data throughput compared to a single-data-rate SRAM at the same clock.
Package and temperature – board-level fit
The 1.26V–1.34V supply is a narrow window — the board's voltage regulator must be accurate to within ±40 mV to stay inside the spec.