Using an SSD (solid state drive) for an external hard drive can have advantages over a traditional hard disk drive (HDD), but may not be the best choice for all users. Here is a quick overview of the pros and cons of using an SSD as an external drive.
Pros of SSD for External Storage
- Faster transfer speeds – SSDs have much faster read/write speeds compared to HDDs, so you can transfer files to and from the external SSD quickly.
- More durable – SSDs have no moving parts, making them more durable and shock-resistant than HDDs.
- Lower power consumption – SSDs use less power, which can help extend laptop battery life.
- Compact size – 2.5″ SSDs are smaller and slimmer than 2.5″ HDDs.
- Silent operation – SSDs make no noise when accessing data.
Cons of SSD for External Storage
- Higher cost per gigabyte – SSDs have a higher upfront cost per gigabyte compared to HDDs.
- Limited capacities – Consumer SSDs currently max out at 4TB. HDDs provide larger capacities.
- Wear out over time – SSDs can wear out after a large number of program/erase cycles.
When an SSD Makes Sense for External Storage
Here are some cases where an SSD is a good choice as an external drive:
- You need faster data transfer speeds over USB or Thunderbolt.
- You travel a lot and want a rugged, durable external drive.
- The external drive will mainly be used for storage and accessing media files like photos, videos, or games.
- You plan to use the drive with laptops and want a low power solution.
When an HDD Makes Sense for External Storage
Here are some cases where a traditional hard drive is a better for external storage:
- You need very high capacity external storage – HDDs are available in larger capacities.
- You are on a tight budget – HDDs provide more storage for the cost.
- The drive will serve as backup storage or network storage and max speed is not needed.
- You plan to fill and erase the drive frequently – HDDs support more write/erase cycles.
SSD vs HDD Cost Comparison
Although SSD prices have come down dramatically in recent years, HDDs are still significantly cheaper in terms of cost per gigabyte. Here’s a quick comparison between SSD and HDD storage (prices as of November 2023):
| Drive Type | Price (1TB) | Price Per GB |
|---|---|---|
| SSD SATA | $80 | $0.08 |
| SSD M.2 NVMe | $100 | $0.10 |
| External SSD | $150 | $0.15 |
| External HDD | $50 | $0.05 |
As you can see, HDDs are about 2-3 times cheaper per gigabyte compared to SSDs. The price gap closes slightly when looking at external drives, but HDDs still offer more storage capacity for the cost.
Max Capacities: SSD vs HDD
For external storage, one of the limitations of SSDs is lower maximum capacities compared to HDDs. Here is how they currently compare:
| Drive Type | Max Capacity |
|---|---|
| External SSD | 4TB |
| External HDD | 18TB |
If you need an external drive with storage beyond 4TB, an HDD is your only option. HDDs offer much larger external storage at around 18TB. Keep in mind these maximums are for consumer drives and capacities in the data center are far higher for both SSDs and HDDs.
Speed Comparison: SSD vs HDD
SSDs have a major advantage over HDDs when it comes to speed. This table compares the sequential read/write performance of SATA and NVMe SSDs vs HDDs:
| Drive Type | Sequential Read | Sequential Write |
|---|---|---|
| SATA SSD | 550 MB/s | 520 MB/s |
| NVMe SSD | 3,500 MB/s | 3,000 MB/s |
| HDD | 150 MB/s | 150 MB/s |
Even SATA SSDs offer 3-4 times higher sequential read/write speeds than HDDs. And the latest NVMe SSDs leave HDDs far behind with over 20x higher performance. Clearly SSDs are much faster, which makes a big difference for external storage use cases that demand high speed data transfers.
Reliability: SSD vs HDD
SSDs don’t have moving parts like HDDs, so they are more resistant to physical shocks and vibration. That makes them generally more reliable in the long run. Here are some reliability factors to consider:
- Annualized Failure Rate (AFR) – SSDs have lower AFR around 0.5-2% compared to 1.5-3% for HDDs.
- Data Recovery – Recovering data from a damaged SSD can be difficult to impossible. HDD recovery is easier in many cases.
- Writes Before Failure – SSDs are limited by total writes before failure. Consumer SSDs last for 200-500 full drive writes. HDDs have no such limit.
Overall, SSDs have the edge for reliability, especially for external use. But a single HDD failure is easier to recover from compared to a dead SSD.
Power Efficiency: SSD vs HDD
This is an important factor to consider for external drives used with laptops. HDDs require more power when active, which can drain laptop batteries faster. SSDs are more efficient especially during random access.
- Active Power (Milliwatts) – HDD: 5000 | SSD: 1000
- Idle Power (Milliwatts) – HDD: 1500 | SSD: 70
SSDs use 3-5 times less power than HDDs when active, and over 20 times less when idle. With fewer components and no moving parts, SSDs draw significantly lower power overall.
Noise and Vibration
Noise and vibration are other considerations for externals drives. HDDs produce audible noise during operation due to the spinning of the platters and movement of the read/write heads. SSDs have no moving parts and are completely silent.
SSDs also produce no vibration versus HDDs which create minute vibration and movement during activity. For portable external drives, an SSD’s noiseless operation and lack of vibration are big advantages.
Cost per GB over Time
While HDDs are far cheaper in terms of cost per gigabyte, SSD prices continue to decline at a faster rate each year. This chart shows how the costs are changing over time:
| Year | HDD Cost per GB | SSD Cost per GB |
|---|---|---|
| 2016 | $0.03 | $0.30 |
| 2018 | $0.02 | $0.13 |
| 2020 | $0.018 | $0.10 |
| 2022 | $0.017 | $0.08 |
Although HDD pricing is also decreasing, SSD pricing is dropping at a rate of 30-35% per year versus 10-15% for HDDs. At this pace SSDs will reach par with HDD $/GB in 3-5 years.
External SSD vs HDD: Which is Better?
So is an external SSD or HDD best for you? Here are some quick recommendations based on common usage scenarios:
- Video editing or other high bandwidth tasks – SSD for the performance.
- Quickly transferring files between external drives – SSD for the transfer speed.
- Frequent travel use with a laptop – SSD for the durability, power efficiency, and silence.
- Archive or backup drive for capacity – HDD for the lower cost per gigabyte.
- Storing large media files like photos/videos – HDD provides more space for the budget.
- Gaming library storage – SSD for faster level loads.
In general, SSD is the better choice for external storage you need to access frequently and speed is important. But HDD remains a cost effective solution for archival, backup, and media storage where maximum capacity for the budget is critical.
Conclusion
SSDs offer major benefits in speed, efficiency, durability, and noise over HDDs. But HDDs continue to offer far larger capacities at a lower cost point. For external storage, SSD is preferred for portability and frequently accessed data, while HDD remains ideal for backup, archival storage, and large media libraries where cost and capacity are critical factors.
As SSD costs continue to decrease, they will become more competitive for mass storage. But HDD tech also continues to advance. In the future, we may see hybrid drives that combine the best of both worlds – SSD for caching hot data and HDD for high capacities. For now, both SSD and HDD retain an important role in the world of external and portable storage solutions.