Fusion Drive and flash storage are two different types of storage technologies used in computers. The main differences between them are:
What is a Fusion Drive?
A Fusion Drive is a hybrid drive developed by Apple that combines a hard disk drive with flash storage. It aims to provide the capacity of a traditional hard drive with the speed of solid state flash storage.
With a Fusion Drive, frequently accessed files are stored on the faster flash storage portion of the drive, while less frequently accessed files are stored on the higher capacity hard drive portion. The macOS operating system handles moving files between the flash and hard drive portions automatically and transparently based on usage patterns.
Some key characteristics of Fusion Drives:
- Combines a hard disk drive and flash storage into a single logical volume.
- Flash portion uses PCIe SSD storage, usually 24GB or 128GB depending on model.
- Hard drive portion uses a standard HDD, usually 1TB or larger.
- Managed by macOS to optimize performance automatically.
- Only available as an option on Mac desktop computers (iMacs and Mac minis).
What is Flash Storage?
Flash storage refers to solid state drives (SSDs) that use flash memory chips to store data. Unlike hard disk drives, flash storage has no moving mechanical parts and data is stored on microchips.
Some key characteristics of flash storage:
- Faster read/write speeds than HDDs.
- Silent operation.
- Lower power consumption.
- More durable and shock-resistant.
- Currently more expensive per gigabyte than HDDs.
- Used in many types of computers and devices.
Differences Between Fusion Drives and Flash Storage
The major differences between fusion drives and dedicated flash storage are:
| Fusion Drive | Flash Storage (SSD) |
|---|---|
| Hybrid drive – combines HDD and flash | Pure flash memory storage |
| Managed automatically by macOS | Not dependent on OS optimization |
| Only available as internal storage on Macs | Used across many devices and computers |
| Set capacities depending on model | Range of capacities available |
| Data moves between HDD and flash | All data stored on flash memory |
| Less expensive per gigabyte than pure SSD | More expensive per gigabyte than HDD |
In summary, a Fusion Drive is Apple’s proprietary hybrid storage solution that combines an HDD and flash into a single drive. Dedicated flash storage like SSDs use only flash memory without any mechanical HDD components.
Performance Comparison
Fusion Drives generally provide better overall performance than hard drives, but not as high performance as pure flash storage SSDs:
- Hard Drive: HDDs have the slowest performance with maximum sustained read/write speeds of around 160MB/s.
- Fusion Drive: Fusion Drives are faster than HDDs for frequently accessed files stored on the flash portion, with speeds over 300MB/s. But less accessed files are stored on the slower HDD portion.
- SSD: Dedicated SSDs with flash memory only provide the fastest performance, with sustained read/write speeds up to 3500MB/s on high-end models.
So while Fusion Drives offer a performance increase over traditional hard drives, they still don’t match the speeds of the fastest SSDs. But they provide a balance of increased speed and large storage capacity.
Speed Test Comparisons
Here are some examples of speed test comparisons between hard drives, Fusion Drives, and SDDs:
| Drive Type | Sequential Read | Sequential Write |
|---|---|---|
| HDD | 150MB/s | 150MB/s |
| Fusion Drive | 300MB/s | 200MB/s |
| SATA SSD | 550MB/s | 520MB/s |
| NVMe SSD | 3500MB/s | 3000MB/s |
These sequential read/write speeds demonstrate the performance differences. Fusion Drives provide better performance than HDDs, but top-end NVMe SSDs are much faster than either Fusion Drives or SATA SSDs.
Usage Scenarios
The best uses cases for Fusion Drives vs dedicated SSDs depend on your performance and capacity needs:
- Fusion Drive: Good option if you need high capacity but also want improved speed for a single internal drive. The automatic file management works best for typical consumer workflows.
- SSD: Provides fastest speeds. Best for applications where sustained read/write performance is critical like video editing, gaming, CAD work.
- SSD + HDD: Combining a dedicated SSD for critical files/apps and a HDD for bulk capacity can provide speed and large storage. Requires more manual file management.
For general home/office use, a Fusion Drive provides a good balance. But for intensive production work and specialized applications, dedicated high-speed SSDs are preferred.
Reliability
Both Fusion Drives and flash storage drives are generally reliable options with a low risk of failure:
- Fusion Drives have the mechanical hard drive component, which has a finite lifespan and risk of mechanical failure over time.
- SSDs don’t have moving parts, so have lower failure rates over time.
- But SSDs do carry a risk of failure of the flash memory cells after extensive write cycles.
Overall, both Fusion Drives and SSDs should provide years of reliable usage under normal conditions. Some key factors affect their longevity:
- Quality – Drives from reliable brands last longer.
- Workload – Heavy workloads shorten lifespan.
- Drive health monitoring – OS tools like SMART help monitor drive status.
- Backup practices – Regular backups minimize risk of data loss.
Following best practices for monitoring drive health, avoiding excessive workloads, and backing up data will maximize the lifespan of both Fusion Drives and SSDs.
Cost Comparison
When comparing costs, Fusion Drives are generally less expensive than an equivalently sized SSD, but more expensive than HDDs:
| Drive Type | 1TB Cost |
|---|---|
| Hard Drive | $50 |
| Fusion Drive | $100 |
| SSD | $150 |
The hybrid Fusion Drive costs more than an HDD but less than an SSD for the same capacity. The flash portion improves performance at a lower cost compared to a full SSD.
Costs can vary between different drive models and capacities. But HDDs are generally the most affordable per gigabyte, while SSDs cost the most for all-flash storage.
Compatibility
Fusion Drives and flash storage have different compatibility considerations:
- Fusion Drives: Can only be used as internal storage on Mac desktops. Not compatible with Mac laptops or other devices. Requires macOS and Thunderbolt ports.
- SSDs: Widely compatible across many devices and operating systems. Can be used as internal or external drives. Often the preferred storage upgrade option.
If you want to upgrade a Mac laptop, you need flash storage like SSDs. Fusion Drives are only an option for Mac desktops. For non-Apple devices, SSDs provide broadly compatible flash storage upgrades.
Upgrading to Flash Storage
For many users, upgrading from a Fusion Drive or HDD to a flash storage SSD provides the best performance boost:
- Replace aging Fusion Drives or HDDs in Macs when possible to notably improve speed.
- Use external Thunderbolt or USB SSDs to add fast storage without opening up devices.
- Take advantage of falling SSD prices to get more flash storage capacity.
When upgrading, clone drives or reinstall operating systems cleanly for optimal SSD performance. Avoid simply migrating existing HDD contents over to SSDs.
Maximize limited internal storage space in laptops with large external SSDs for additional capacity. Use high-speed connections like Thunderbolt where possible.
Conclusion
In summary:
- Fusion Drives provide a balance of capacity and improved performance compared to HDDs.
- SSDs offer the fastest speeds but at a higher price per gigabyte.
- For computers that support it, Fusion Drives give a performance boost over HDDs while adding internal capacity.
- For optimal speed, dedicated SSDs are preferred, either as internal replacements or external storage.
As SSD prices fall and speeds increase, flash storage upgrades provide the best way to dramatically improve computer performance. But Fusion Drive technology retains some unique advantages for select Mac models, striking a good balance between speed and storage capacity.
