Using an external SSD as a boot drive is absolutely possible, though there are some important considerations to keep in mind. An external SSD connected via Thunderbolt, USB 3.0, or USB-C can provide fast performance comparable to an internal drive, allowing you to run your operating system and programs directly from the external SSD. However, there are tradeoffs in terms of convenience, portability, and long-term reliability that are worth examining before relying solely on an external SSD for daily computing and booting.
Quick Overview: Using an External SSD as a Boot Drive
In short, yes you can use an external SSD as your primary boot drive and store your operating system, programs, and files on it. The advantages are:
- External SSDs are portable and can work across different computers
- SSD performance is fast compared to external hard drives
- Easy to set up as primary boot drive on Macs and PCs
Potential downsides to consider:
- Need available Thunderbolt, USB 3.0, or USB-C ports to connect external SSD
- Less convenient having an external drive to carry around and connect
- External enclosures can fail, risking data loss if SSD itself fails
Overall using an external SSD as a boot drive can work very well, provided you understand the convenience tradeoffs and take precautions for reliability and backups.
Advantages of Using an External SSD as a Boot Drive
There are some great reasons you may want to consider using an external SSD over an internal drive as your primary boot volume:
- Portability: External SSDs are designed to be portable and transportable between different computers. You can bring your entire work environment with you in your pocket or bag.
- Cross-platform versatility: A bootable external SSD can work equally well with Macs or Windows PCs, allowing you to use the same drive as your main boot volume across compatible devices.
- Upgrade convenience: Upgrading to a larger or faster external SSD is a simpler process than replacing an internal drive, not requiring opening up your computer.
- Data security: If your external SSD is encrypted, you can more easily keep your data accessible to only you, even when switching between devices.
- Reliability: External SSDs based on flash memory have no moving parts and are less prone to failure from shock or drops.
In addition, today’s external SSDs offer excellent performance rivaling internal SATA and even NVMe SSDs, thanks to high-speed interfaces like Thunderbolt 3 and USB 3.2 Gen 2×2.
Disadvantages of Using an External SSD as a Boot Drive
Using an external SSD as your primary boot drive also comes with some downsides to consider:
- Connectivity limitations: You’ll need an available Thunderbolt, USB-C, or USB 3.0 port on your computer to connect the external SSD. If ports are limited, this can cause issues.
- Limited portability: While external SSDs are designed to be portable, you’ll need to remember to connect and disconnect the drive when moving between computers. An internal boot drive is already built-in.
- Enclosure reliability: While the SSD itself is reliable, external enclosures can potentially fail or have issues like a failed USB port, which could cause data loss.
- Higher cost: External SSDs usually have a price premium over similar internal SSDs due to the enclosure and convenience features.
Functionally there is very little difference between booting from an external vs. internal SSD, so the disadvantages mainly come down to the inconvenience of using an external device as your primary system drive.
Performance of External SSDs vs. Internal SSDs
In terms of real-world performance, today’s high-end external SSDs can match and even outperform many internal SATA and NVMe SSDs, thanks to high-speed interfacing technologies:
| SSD Type | Interface | Max Sequential Read | Max Sequential Write |
|---|---|---|---|
| External SSD (Thunderbolt 3) | Thunderbolt 3 | 2,800+ MB/s | 2,800+ MB/s |
| External SSD (USB 3.2 Gen 2×2) | USB 3.2 Gen 2×2 | 2,000+ MB/s | 2,000+ MB/s |
| Internal SATA SSD | SATA | 550+ MB/s | 500+ MB/s |
| Internal NVMe SSD | PCIe 3.0 x4 | 3,500+ MB/s | 3,000+ MB/s |
As you can see, Thunderbolt 3 and USB 3.2 Gen 2×2 external SSDs can provide sequential read/write speeds exceeding what’s possible even with the fastest internal SATA SSDs. This allows for incredibly fast booting and loading times by removing interface bottlenecks.
External SSD performance can still lag behind the fastest internal PCIe 4.0 and NVMe drives in benchmarks. But in real-world use, the differences are marginal for most users. An external SSD via Thunderbolt 3 or USB 3.2 Gen 2×2 can deliver great performance as a boot drive.
Steps for Using an External SSD as a Boot Drive
If you’ve decided you want to use an external SSD as your primary boot drive, here are the basic steps involved in setting that up:
- Select and purchase an external SSD. Make sure it has a high-speed interface like Thunderbolt 3, USB 3.2 Gen 2×2, or at least USB 3.0. SSD capacity depends on your needs.
- Back up any data on your existing boot drive you wish to migrate to the new external SSD.
- Create a bootable installer for your operating system on the new external SSD.
- Boot from the external SSD and install your OS cleanly on it.
- Install any applications and restore data from backup.
- Configure OS settings like sleep and hibernation appropriately.
That covers the basic workflow. There are some specific steps depending on your computer and OS that we’ll cover next.
Using External SSD as Boot Drive on Windows
Here is the detailed process for setting up an external SSD as the primary boot drive on a Windows PC:
- Attach the external SSD via Thunderbolt, USB-C, or USB 3.0 port. Make sure the drive is recognized.
- Use the Microsoft Media Creation Tool to create a Windows bootable installer on the external SSD.
- Boot from the external SSD installer drive, then install Windows cleanly on external SSD.
- Install drivers for external SSD enclosure components as needed.
- Go to Settings > Power & Sleep to configure sleep and hibernation appropriately.
- Move personal files from old boot drive via external hard drive or cloud storage.
- Enjoy using your portable external SSD Windows drive!
The process is very straightforward. Make sure to configure Windows power saving modes properly so your external SSD does not unexpectedly power down and crash.
Using External SSD as Boot Drive on Mac
Here is the process for using an external SSD as your main boot drive on a Mac:
- Connect external SSD to Mac via Thunderbolt 3 or USB-C port.
- Create macOS installer on external SSD using createinstallmedia command in Terminal.
- Boot from external SSD installer and install fresh macOS system on external SSD.
- Migrate data from old boot drive to external SSD using Migration Assistant.
- Configure Energy Saver settings to prevent system sleep when external SSD detached.
- Enjoy your new portable external SSD macOS boot drive!
The steps are very similar to Windows. Be sure adjust Energy Saver settings so your Mac does not go to sleep when your external SSD is detached. Keep the drive attached when the system is on.
Tips for Running OS and Programs from External SSD
If you decide to use an external SSD as your primary operating system and program drive, here are some useful tips:
- Only disconnect or power down external SSD when computer is fully shut down.
- Use a high-quality USB-C/Thunderbolt cable for reliable connections.
- Consider password-protecting drive encryption in case external SSD is lost or stolen.
- Ensure external SSD enclosure has good heat dissipation to maintain performance.
- Have a backup image of your OS and programs on a second drive in case external SSD fails.
- Eject external SSD properly before unplugging from your computer.
Following these tips will help ensure your external SSD continues running smoothly and reliably as your daily operating system drive.
Optimizing Windows for External SSD Boot Drive
For Windows systems, optimize these specific settings for best performance booting from external SSD:
- Disable hibernation mode
- Disable fast startup
- Configure sleep settings appropriately
- Disable SuperFetch and Prefetch
- Disable scheduled optimization tasks
These adjustments will prevent unexpected closure of external SSD connections and reduce unnecessary writes.
Optimizing Mac for External SSD Boot Drive
On Macs booting from external SSD, be sure to optimize:
- Disable Power Nap
- Prevent computer and display sleep when drive detached
- Exclude external SSD from Spotlight indexing
- Disable local Time Machine backups to external SSD
Following these steps will help prevent drive disconnections and reduce unnecessary operations on the external SSD.
Comparing Thunderbolt, USB-C, USB 3.0 Performance
For the best external SSD performance, you’ll want to choose the fastest interface available on your computer. Here is how the common options compare:
| Interface | Speed | Platforms Supported |
|---|---|---|
| Thunderbolt 3 | Up to 40Gbps | Macs (2016 and later) Some PCs |
| USB 3.2 Gen 2×2 | Up to 20Gbps | Newer PCs and Macs |
| USB 3.2 Gen 2 | Up to 10Gbps | Most modern PCs and Macs |
| USB 3.0 | Up to 5Gbps | Most PCs and Macs (last 10 years) |
As you can see, Thunderbolt 3 is fastest, but USB 3.2 Gen 2×2 gets very close to its performance. Even USB 3.0 is sufficient for external SSD booting for many.
Comparing External SSD Enclosures
The design and quality of the external enclosure also impacts performance and reliability. Here are key factors to consider:
- Interface support: Look for enclosures with Thunderbolt 3, USB 3.2 Gen 2×2, or at least USB 3.0.
- Thermal design: Enclosures that better dissipate heat will maintain SSD performance.
- Power delivery: Some enclosures ensure stable consistent power to the SSD which reduces errors.
- Compatible SSDs: Check enclosure SSD compatibility and upgrade limitations.
- Ruggedness: Metal and rubberized enclosures can better withstand shock and vibration.
- Warranty: Opt for enclosures with 3 years or longer warranties for more coverage.
Higher-end external SSD enclosures will offer some combination of these attributes for a more optimal and reliable external booting experience.
Frequently Asked Questions
Is booting from external SSD the same as internal?
Booting from an external SSD works very similarly to booting from an internal drive, provided you have the proper interface like Thunderbolt 3. The boot process itself will be identical. The main differences are the additional steps of connecting/disconnecting the external SSD and somewhat higher latency.
Can I clone existing system to external SSD?
Yes, you can clone an existing internal system drive to an external SSD using free disk cloning software like Macrium Reflect (Windows) or Carbon Copy Cloner (Mac). This allows you to easily migrate your OS, programs, and data from an old drive to your new external SSD.
Is booting from external SSD slower?
Booting from external SSD can be a few seconds slower in some cases, but often not noticeably. Thunderbolt 3 and the best USB 3.2 interfaces have minimal performance impact. Lower-end USB 3.0 external drives may have longer boot times.
Can I play games from external SSD?
Yes, you can play games directly off an external SSD. Game loading times will benefit greatly from the improved read speeds versus a HDD. For best results, use an external SSD enclosure with Thunderbolt 3 or high-end USB 3.2 Gen 2×2 speeds.
Should I keep applications on external SSD?
For frequently used applications, installing them directly on your external boot SSD will provide fast launch times. For apps you use infrequently, consider installing them on a secondary internal drive instead.
Conclusion
Booting your system from a speedy, high-performance external SSD is absolutely viable. Thunderbolt 3 and USB 3.2 Gen 2×2 external SSDs offer compelling performance rivaling internal drives. While less convenient than an internal boot drive, external SSDs provide great flexibility, transportability, and ease of upgrades.
Just be sure to choose an enclosure optimized for sustained performance and take precautions against potential external SSD failure. Used properly, an external SSD can serve as a quick, convenient, and portable boot drive.