Harddisk drive vs RAM - a comparison

Harddisk drive and Random access memory / Why RAM is considered as fastest when compared to hard disk? / Harddisk vs RAM / Computer performance and storage devices

Harddisk drive vs RAM - a comparison

	Hard Drive	RAM
Size	Large sizes Internal drives – Max 8 TB for desktops External drives – Max 8 TB	Small sizes Max 32 GB (as per the year 2015 for desktop computers)
Storage	Permanent (Non-volatile) Do not lose data due to power loss (Switched off).	Temporary (Volatile) Lose all data due to power loss (Switched off).
Time taken to read files	Vary for files. Depends on the size and location of a file.	Fixed for files. We are able to pick the data directly as per the size.
Units of storage	Bytes	Bytes
Requires power to retain content	No Hard drives retain contents as the writing surfaces are magnetic	Yes RAM cannot retain the content due to power loss is because of RAM is made up of circuits.
Made up of	Magnetic components	IC (Integrated Circuits) components
Storage capacity vs performance	No performance improvement. Increase in the size of the hard disk, say, from 500 GB to 1 TB would not show any performance improvements.	Performance changes. Increase in the size of RAM, say, from 4 GB to 8 GB will definitely show some improvements in performance.
How the files are stored?	Magnetically	Electronically
Flexibility in space	Flexible. We can delete unwanted files if we need more space (on the same disk)	Not flexible. If any program does not function due to less memory size, you need to upgrade your memory to make that program work.
Hardware dependency	Works on 32 bit and 64 bit computers	Upto 4 GB – supported by 32 bit computers Upto and above 4 GB – supported by 64 bit computers