A Peek Into the Future: Results from PCIe Gen 6 SSD Simulations

Author: Young Pac, VP of Business Development, FADU Collection: 2025 OCP Global Summit - Expo Hall Sessions

Summary

FADU, an SSD controller company, presents simulation results showing PCIe Gen 6 SSDs can achieve 6.9 million IOPS per drive at 4KB random read, closely approaching the theoretical maximum for the interface. The presentation argues that the enterprise SSD market is splitting into three distinct segments -- standard SSDs (TLC/QLC, 4-32 TB, 0.3-3 DWPD), nearline SSDs (QLC or beyond, 128-256 TB, <0.1 DWPD with 16-32KB+ page sizes), and NAND as memory/SCM (SLC, 1-4 TB, >10 DWPD with 512-byte access granularity). Each segment has fundamentally different performance, endurance, and capacity characteristics optimized for distinct workloads.

The datacenter layout analysis for 1 exabyte of storage reveals that nearline SSDs require only 14 racks versus 82 for HDD servers and 869 for current SSD servers, with total allocated power of 119 kW versus 697 kW (HDD) and 7.39 MW (SSD). This represents an 83% saving of space and allocated power compared to HDD racks. However, the presentation identifies five major challenges: CPU saturation at 100-200K IOPS per core, increasing minimum SSD sizes due to NAND layer counts, 25W power limits per drive, thermal constraints in dense configurations (40 drives at 25W = 1 kW cooling needed), and DRAM bandwidth limitations. Solutions include TCP offload, CPU bypass via RDMA, 800G+ networking, and potentially liquid cooling for SSDs.