DRAM-less SSD + HMB詳細。HMB(Host Memory Buffer・NVMe spec)・DRAM Cache代替で System RAM 40-128MB割当(1GB以下・Mainboard資源)・FTL(Flash Translation Layer)mapping table保持・Random IOPS DRAM-less typical 80-90% of DRAM SSD・実用差: Boot/App ほぼ同等・Random Write large file -15-20%(Photoshop/Premiere)・Sustained Write SLC Cache依存・$3-5/TB cheap vs DRAM SSD・例: Samsung 990 EVO(DRAMless)・Crucial P3 Plus・WD Blue SN5000・Lexar NM790・Kingston NV3・選択基準: Boot drive Mass appeal = DRAM-less OK・Pro Workstation Adobe重い = DRAM SSD推奨・2026年 Consumer SSD 70%+ DRAM-less・cost dominate market。