External SSD Selection Guide for FFmpeg/Video Editing

When it comes to video conversion and editing work with FFmpeg, storage selection significantly affects work efficiency. This guide explains FFmpeg-specific requirements and practical usage that general SSD selection guides don’t cover.

Key Terms Used in This Article

Why FFmpeg Needs an SSD

Encoding work with FFmpeg has different characteristics from simple file reading and writing.

FFmpeg-Specific Storage Requirements

1. Large Volume of Temporary File Processing

FFmpeg generates a large volume of temporary files during processing. Especially in 2-pass encoding, it writes statistical data in the first pass and reads it while encoding in the second pass. During this process, low random access performance significantly extends overall processing time.

2. Speed Maintenance During Continuous Writes

4K video encoding involves continuous data writing for tens of minutes to hours. Some inexpensive SSDs experience speed drops to 1/3 or less when cache depletes. For example, when writing a 50GB 4K video, it may start at 1000MB/s but drop to 300MB/s midway.

3. I/O Load During Parallel Processing

When processing multiple videos simultaneously, disk I/O concentrates. With HDDs, seek time occurs and processing becomes significantly slower, but SSDs are strong at random access, so speed doesn’t drop even with parallel processing.

Measured: Encoding Time Comparison

Actual results from processing a 60-minute 4K video (H.265→H.264 conversion, CRF23):

With a fast external SSD, you can get almost the same performance as an internal SSD.

Guide to Selecting Without Mistakes

Common Purchase Mistakes

1. Overlooking USB Standard

Even if it says “USB 3.2 compatible,” it might be Gen1 (5Gbps). Always check for “Gen2 (10Gbps)” or “Gen2x2 (20Gbps).”

2. Computer Port Limitations

Even if the SSD supports 20Gbps, if your computer’s USB port only supports 10Gbps, speed is limited to 10Gbps.

Warning for Mac Users:

• MacBook Air (M1/M2): Up to USB 3.1 Gen2 (10Gbps)
• MacBook Pro (M1 Pro and later): Supports Thunderbolt 4 (40Gbps)

Before purchasing, check by going to “About This Mac” → “System Report” → “USB.”

3. Cable Quality

Even with a 20Gbps-capable SSD, if the included cable only supports 10Gbps, a separate high-quality cable purchase may be necessary.

How to Choose Connection Standards

Importance of Backup Strategy

SSDs fail suddenly. Always backup important data to another drive or cloud.

Recommended Configuration:

• Work: External SSD (fast)
• Backup: External HDD (large capacity, low cost)
• Cloud: Final products only

Recommended Configurations and SSDs by Use Case

Weekend Hobby Level (A few times per month, editing HD to 4K video)

Recommended Specs:

• Capacity: 1TB
• Speed: USB 3.2 Gen2 (10Gbps, effective speed 500-1000MB/s)
• Budget: 10,000-20,000 yen

Reason: When processing few videos and slightly longer encoding time is acceptable, cost-performance focus is sufficient. Portable SSDs are convenient and recommended.

Recommended Products:

Semi-Pro (YouTubers etc., editing 4K video several times per week)

Recommended Specs:

• Capacity: 2TB or more
• Speed: USB 3.2 Gen2x2 (20Gbps, effective speed 2000MB/s) or Thunderbolt 4 (40Gbps)
• Budget: 25,000-45,000 yen

Reason: When working on multiple projects simultaneously and speed directly affects revenue, high-speed models are recommended. Speed maintenance performance during continuous writes is also important.

Recommended Products:

Note: Mac M1/M2 Air Users Even with USB 3.2 Gen2x2 (20Gbps) products, if Mac side only supports 10Gbps, effective speed is limited to about 1050MB/s. MacBook Pro M1 Pro and later have no restrictions.

FFmpeg Usage Tips:

# Parallel processing of multiple videos (4 parallel example)
find . -name "*.mp4" | xargs -P 4 -I {} ffmpeg -i {} -c:v libx264 -crf 23 output/{}.mp4

With external SSDs, speed degradation is minimal even with parallel processing, significantly reducing work time.

Professional (Daily handling of 8K/RAW material)

Recommended Specs:

• Capacity: 4TB or more
• Speed: Thunderbolt 4/USB4 (40Gbps, effective speed 3000MB/s+)
• Configuration: NVMe SSD + External enclosure (assembly type)
• Budget: 50,000-80,000 yen

Reason: 8K video reaches several GB per minute, requiring large capacity and maximum speed. Assembly types allow future SSD replacement and are more cost-effective long-term.

Recommended Configurations (Assembly Type):

Maximum Performance Configuration (With Cooling Fan)

Cost-Performance Configuration

About Ready-Made (Portable Type):

As of October 2025, there are almost no ready-made external SSDs (4TB or more) supporting Thunderbolt on the market. For professional large-capacity, high-speed storage, the assembly type (NVMe SSD + external enclosure) above is mainstream. Assembly takes about 5 minutes without tools and has the advantage of being able to replace only the SSD in the future.

Heat Countermeasures: Heat becomes an issue during long encoding. Enclosures with built-in cooling fans (like ACASIS) or cooling with small USB fans can prevent speed degradation.

Actual Usage Experience: Author currently uses ACASIS TBU405Pro M1 + WD_BLACK SN850X 2TB combination as iMac boot drive. Fan is quiet, no heat-related speed degradation even with long-term use. Assembly is tool-free and takes about 5 minutes.

Practical Tips for FFmpeg Users

Efficient Work Directory Structure

/Volumes/WorkSSD/
├── input/          # Original videos
├── temp/           # Temporary files (for 2-pass encoding)
├── output/         # Completed videos
└── scripts/        # FFmpeg scripts

Points:

• Periodically delete temp/ to ensure space
• Separating input and output makes management easier

Encoding Settings and Required Capacity Guidelines

For 2-pass encoding, an additional few MB to tens of MB is needed for statistics files.

Parallel Processing Ideas with Multiple SSDs

For speedup, separating input and output on different SSDs is effective:

# Example using SSD1 (input) and SSD2 (output)
ffmpeg -i /Volumes/SSD1/input.mp4 -c:v libx264 -crf 23 /Volumes/SSD2/output.mp4

Especially when processing large volumes of video, distributing I/O can improve speed.

Heat and Speed Degradation Countermeasures

Symptoms: About 30 minutes after encoding starts, when SSD temperature exceeds 60℃, speed decreases (thermal throttling).

Countermeasures:

1. Choose enclosures with built-in cooling fans (ACASIS TBU405Pro, etc.)
2. Cooling with small USB fans
3. Place on metal heat sink
4. Divide encoding and create time for SSD to cool

Purchase, Setup, and Troubleshooting

Pre-Purchase Checklist

• Capacity suitable for use case (1TB/2TB/4TB)
• USB standard meets requirements (Gen2 or higher recommended)
• Compatible with computer’s USB port
• Included cable standard sufficient
• Reviews mention “speed degradation during continuous writes”
• Warranty period sufficient (3-5 years recommended)

Setup Procedure

Mac:

1. Connect SSD
2. Open “Disk Utility”
3. Select SSD → “Erase” → Format “APFS” or “exFAT” (Windows compatible)
4. Name and “Erase”

Windows:

1. Connect SSD
2. Open “Disk Management”
3. Right-click new disk → “Initialize Volume”
4. “New Simple Volume” → Format “NTFS” or “exFAT” (Mac compatible)

Common Troubles and Solutions

Trouble 1: Speed is slow (less than half of standard)

Causes:

• Connected to USB 2.0 port
• Using old cable
• Cable too long (2m or more risks speed degradation)

Solutions:

• Connect to USB 3.2 or higher port
• Use high-quality short cable

Trouble 2: Not recognized

Causes:

• Format not done
• Cable poor contact
• Power shortage (bus power insufficient)

Solutions:

• Check in Disk Utility/Disk Management
• Unplug and replug cable
• Connect via powered USB hub

Trouble 3: Connection drops midway

Causes:

• Thermal throttling from heat
• Power shortage

Solutions:

• Strengthen cooling
• Use self-powered USB hub

2025 Latest Trends

USB4 and Thunderbolt 5

As of 2025, USB4 (40Gbps) is entering its popularization phase, and Thunderbolt 5 (80Gbps) compatible products are beginning to appear. However, prices are still high, and 40Gbps is currently sufficient for FFmpeg video processing, so there’s no need to forcibly choose the latest standards.

SSD Price Trends

Since late 2024, NAND flash memory prices have been trending downward, and large-capacity SSDs (2TB or more) are becoming more affordable in 2025. As 4K video editing becomes more common, 2TB is becoming the standard choice.

Summary

Points for choosing the optimal external SSD for FFmpeg video processing:

1. Understand FFmpeg-specific requirements: Random access performance and speed maintenance during continuous writes are important
2. Choose according to use case: For hobby use 1TB/10Gbps, for semi-pro 2TB/20Gbps, for pro 4TB/40Gbps
3. Prevent mistakes with confirmation: Check USB standard, computer-side port, cable quality
4. Practical utilization: Optimize with work directory structure, parallel processing, heat countermeasures
5. Backup strategy: Use SSDs for work, HDDs for backup

With appropriate storage selection, FFmpeg video processing becomes comfortable.

Related Articles

• FFmpeg Installation, Usage, Options, Commands