What is the difference between FileStream and MemoryStream?

Question

ICSM Computer · Answer

FileStream and MemoryStream are both part of the .NET
System.IO namespace, and while they both inherit from Stream, they serve
very different purposes.
FileStream vs MemoryStream
Feature
FileStream
MemoryStream
Storage Medium
Interacts with a file on disk
Uses memory (RAM) as the data store
Performance
Slower (disk I/O latency)
Faster (memory access)
Persistence
Persistent (data remains after app closes)
Volatile (data lost when app exits or disposed)
Use Cases
Reading/writing files, file-based logs, etc.
In-memory data processing, temp buffers, etc.
Constructors
Requires file path or handle
Uses byte arrays or default in-memory buffer
Requires Cleanup
Yes — can lock file until disposed
Yes — disposes RAM used by buffer
Examples
FileStream Example (write to disk):
using (var fs = new FileStream("data.txt", FileMode.Create, FileAccess.Write))
{
    byte[] data = Encoding.UTF8.GetBytes("Hello, FileStream!");
    fs.Write(data, 0, data.Length);
}
MemoryStream Example (write to memory):
using (var ms = new MemoryStream())
{
    byte[] data = Encoding.UTF8.GetBytes("Hello, MemoryStream!");
    ms.Write(data, 0, data.Length);
    // Reset and read back
    ms.Position = 0;
    var reader = new StreamReader(ms);
    string text = reader.ReadToEnd();
}
When to Use
Use FileStream when:
You need to read/write actual filesYou want persistent storageYou're working with large files that don’t fit into memory
Use MemoryStream when:
You want fast, temporary in-memory processingYou're working with byte arrays, serialization, or image manipulationYou want to avoid disk I/O for performance

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What is the difference between FileStream and MemoryStream?

ICSM Computer

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1 Answers

`FileStream` vs `MemoryStream`

Examples

FileStream Example (write to disk):

MemoryStream Example (write to memory):

When to Use

Use `FileStream` when:

Use `MemoryStream` when:

Liked By

Feature	`FileStream`	`MemoryStream`
Storage Medium	Interacts with a file on disk	Uses memory (RAM) as the data store
Performance	Slower (disk I/O latency)	Faster (memory access)
Persistence	Persistent (data remains after app closes)	Volatile (data lost when app exits or disposed)
Use Cases	Reading/writing files, file-based logs, etc.	In-memory data processing, temp buffers, etc.
Constructors	Requires file path or handle	Uses byte arrays or default in-memory buffer
Requires Cleanup	Yes — can lock file until disposed	Yes — disposes RAM used by buffer