The speed of a hard disk drive is determined by a variety of factors including the disk rotation speed, disk interface, and cache size. Over the years, advances in hard disk technology have steadily increased drive performance. In the past decade, solid state drives (SSDs) have emerged as a major advancement, offering significant speed improvements over traditional mechanical hard drives.
Mechanical Hard Drives
Mechanical hard disk drives store data on spinning magnetic platters. The speed of mechanical drives is largely determined by the rotational speed of the disks inside the drive, measured in revolutions per minute (RPM). Faster RPMs allow data to be accessed more quickly.
Some key innovations in mechanical drive speed include:
- 5400 RPM – Common in entry-level consumer drives
- 7200 RPM – Faster, used in mainstream and performance drives
- 10,000 RPM – Enterprise-class high performance drives
- 15,000 RPM – Top-end drives used in high throughput server environments
In addition to disk RPM, the interface between the drive and computer impacts performance. Common mechanical drive interfaces include:
- PATA – 133 MB/s maximum throughput
- SATA – 600 MB/s maximum throughput
- SAS – 1200 MB/s maximum throughput
Higher interface bandwidth enables faster data transfer between the PC and the hard drive.
Solid State Drives
Solid state drives (SSDs) offer a dramatic speed increase compared to mechanical drives. SSDs use flash memory chips rather than magnetic disks to store data. This allows SSDs to read and write data much faster than mechanical drives.
Some key advantages of SSDs include:
- Faster access times – SSDs can access data in microseconds rather microseconds.
- Faster sequential read/write – SSDs have up to 550+ MB/s sequential read/write speed.
- Greater durability – No moving parts makes SSDs better able to withstand shock/vibration.
Early SSD interfaces matched traditional mechanical drives, but newer interfaces take better advantage of SSD capabilities:
- SATA 3 – Up to 600 MB/s throughput
- PCIe – Up to 4 GB/s throughput
- NVMe – Up to 3.5 GB/s throughput
NVMe is currently the fastest interface available for SSDs, offering extremely high bandwidth to minimize bottlenecks.
Fastest Hard Drive Options
For the absolute fastest hard drive speeds currently available, top options include:
- 15,000 RPM SAS mechanical drive – Offers sustained transfer speeds up to 255 MB/s.
- SATA 3 SSD – SATA 3 SSDs with sequential reads up to 550 MB/s.
- PCIe NVMe SSD – PCIe Gen3 x4 NVMe SSDs with over 3.5 GB/s throughput.
Of these options, PCIe NVMe SSDs currently offer the fastest hard drive performance. The combination of SSD technology with PCIe and NVMe enables unprecedented levels of bandwidth. Whereas 15,000 RPM mechanical drives top out around 255 MB/s, the latest PCIe Gen 4 NVMe SSDs can deliver sequential read speeds over 7,000 MB/s.
This chart compares maximum sequential read speeds of popular hard drive options:
| Hard Drive Type | Interface | Max Read Speed |
|---|---|---|
| 5400 RPM HDD | SATA | Up to 120 MB/s |
| 7200 RPM HDD | SATA | Up to 210 MB/s |
| 10,000 RPM HDD | SAS | Up to 255 MB/s |
| 15,000 RPM HDD | SAS | Up to 255 MB/s |
| SATA 3 SSD | SATA | Up to 550 MB/s |
| PCIe NVMe SSD | PCIe Gen 3 | Up to 3,500 MB/s |
| PCIe NVMe SSD | PCIe Gen 4 | Up to 7,000 MB/s |
Factors in Hard Drive Speed
It’s important to recognize that sustained real-world speeds may be lower than maximum throughput numbers. Several factors play a role in determining real-world hard drive performance:
- Disk RPM – Faster spinning disks have higher throughput.
- Interface bandwidth – The data pipeline between drive and PC impacts speed.
- Access time – Time required to locate stored data.
- Queue depth – Parallel read/write operations improve throughput.
- Workload type – Performance varies for sequential, random, mixed workloads.
- File size – Bigger files are more efficient to read/write sequentially.
- Fragmentation – Scattered files require more mechanical head movement.
Benchmarking utilities that simulate different types of real-world file operations and access patterns can provide a more accurate speed assessment.
Conclusion
PCIe NVMe SSDs currently deliver the fastest hard drive performance thanks to lightning fast flash memory combined with PCIe and NVMe interfaces capable of massive bandwidth over 4 GB/s. Top-end 15,000 RPM SAS mechanical drives max out under 300 MB/s while high-end PCIe Gen 4 NVMe SSDs can sustain over 7 GB/s sequential read speed. For applications requiring uncompromising speed to handle huge files and data sets, PCIe NVMe SSDs are the clear choice.