RAM vs SSD
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Spec-based comparison. We have not tested these products. Definitions and figures below come from the linked Micron, JEDEC-related manufacturer pages and SSD datasheets.
Short verdict
RAM (system memory) holds data the CPU is using right now; an SSD stores files and programs when power is off. They solve different problems. More RAM does not replace a full drive, and a fast SSD does not give you the same working set as DRAM. Micron describes DDR5 as fifth-generation double-data-rate DRAM — “designed for fast data access while a system is running” (Micron DDR5). An SSD such as the Samsung 870 EVO stores data in NAND flash with a stated TBW endurance and keeps it without power (Samsung datasheet).
Key differences
| RAM (e.g. DDR5 DRAM) | SSD (NAND flash) | |
|---|---|---|
| Job | Working / main memory for the CPU | Persistent storage for OS, apps, files |
| Volatility | Loses contents when power is removed (DRAM) | Non-volatile — data remains without power |
| Technology example | DDR5 SDRAM, data rates 4800–8800 MT/s listed by Micron (Micron) | SATA or NVMe SSD; e.g. 870 EVO up to 560 MB/s sequential read (datasheet) |
| Typical form | DIMM / SO-DIMM modules | 2.5-inch or M.2 module |
| Wear model | Not rated in TBW the way SSDs are | Flash wear rated as TBW (e.g. 600 TBW for 870 EVO 1TB) |
| Mixing generations | DDR4 modules do not fit DDR5 boards (Micron) | SATA vs NVMe must match the available slot/cable (NVMe vs SATA) |
What the differences mean
Speed vs persistence. DRAM exists so the processor can keep an active working set in a technology built for low-latency access while the machine is on (Micron). NAND flash SSDs exist so gigabytes to terabytes of data survive power-off and cost far less per bit than DRAM at consumer capacities — with endurance limits expressed as TBW.
You usually need both. Microsoft Flight Simulator 2024 lists separate RAM requirements (16GB minimum, 32GB recommended) and still needs disk space for the install (Steam). Short on RAM, the OS pages data to disk (feels slow); short on SSD space, you cannot install or save files.
“Unified memory” vs SSD. On some platforms the CPU/GPU share a pool of DRAM marketed as unified memory. That pool is still working memory, not a substitute for the device’s flash storage. We only describe a specific Apple or SoC design when we can cite that vendor’s documentation for the exact model — omitted here unless verified per model.
FAQ
Can I use an SSD as RAM? Operating systems can use disk space as virtual memory / pagefile / swap. That is slower than DRAM and is not the same as installing more DDR5. We do not claim it “turns an SSD into RAM.”
Does a faster SSD replace upgrading RAM? No. They address different bottlenecks. Check the application’s stated RAM minimum/recommended figures and your free storage capacity separately.
DDR5 vs NVMe — which first? Neither is a swap for the other. Interface choice for storage: NVMe vs SATA. What an SSD is: What is an SSD?.