Memory and Storage

	RAM Random Access Memory	HDD Hard Disk Drive	SSD Solid State Drive	NVMe SSDs Non-Volatile Memory Express
Primary Function	Temporary storage of files and programs (open files)	Permanent low speed storage of all programs and data	Permanent fast speed storage of all programs and data	Permanent very fast speed storage
Typical Capacity	Smaller amount (typically 4 GB - 16 GB).	Larger amount (240GB to 2 TB or more).	500GB to 8TB	500GB to 8TB
Nature of Storage	Temporary storage of files and programs	Permanent storage of files and programs	Permanent storage of files and programs	Permanent storage of files and programs
Analogy	Like your real desktop - has only your open, current work	Like a file cabinet - has long-term storage - copies files slowly	Like a high-speed searchable room of files - huge files like a DVD are copied in minutes	Even faster - huge files are copied in seconds
Data Retention (Power Off)	Contents disappear when you power off the computer	Contents remain when you power off the computer	Contents remain when you power off the computer	Contents remain when you power off the computer
Data Retention (System Crash)	Contents disappear when the computer crashes	Contents remain	Contents remain	Contents remain
Physical Composition	Consists of chips (integrated circuits)	Consists of a HDD (spinning disks and movable read/write heads)	Consists of chips (NAND flash memory)	Consists of chips (NAND flash memory)
Data Handling (Save)	A temporary copy of the opened file(s) and all changes are kept in RAM until the file(s) is saved.	Until your changes are saved, the original file(s) remains on the HDD. Once saved, the new changes are written to the HDD.	Until your changes are saved, the original file(s) remains on the SSD. Once saved, the new changes are written to the SSD.	Optimizes the speed at which changes are written to compatible SSDs.
Speed	Fast and getting faster.	Slower (mechanical parts)	Much faster than HDDs.	Significantly faster than SATA-based SSDs
Connection Type	Connected via DIMM slots on the motherboard.	Typically connected via SATA IDE interface.	Typically connected via SATA or NVMe (M.2) interface.	Utilizes PCIe M.2 or U.2 for the fastest connection
Impact on Performance	Crucial for multitasking, video editing, and gaming	Affects boot times and overall application loading/saving speeds	Dramatically improves boot times and application responsiveness	Provides the highest performance
Cost	Higher cost per GB compared to HDDs.	Lower cost per GB compared to SSDs.	Higher cost per GB than HDDs, but decreasing.	Generally higher due to performance benefits.
Primary Advantage	Fast, temporary workspace for active data.	Large, inexpensive, permanent storage.	Fast, durable, and more compact permanent storage.	Ultra-fast data transfer for modern storage.