NVMe vs SATA vs USB vs hard drive: what real drives actually deliver
Drafted from every result uploaded to DiskBoard since November 2023.
Everyone knows NVMe is faster than SATA and SATA is faster than USB. Fewer people know by how much, in a real computer, with a real cable and a real enclosure. Here is the answer from every benchmark DiskBoard users have uploaded, grouped by how the drive is connected.
Median speed by connection
Sequential test, 1 MB buffer, one thread. Cached results removed (method at the end). MB/s.
| Connection | Results | Read | Write |
|---|---|---|---|
| Apple silicon internal SSD | 106 | 2,452 | 3,035 |
| NVMe (internal) | 5,405 | 2,181 | 1,833 |
| SATA SSD (internal) | 1,075 | 435 | 340 |
| USB external SSD | 1,041 | 408 | 386 |
| USB flash stick | 26 | 366 | 314 |
| SD card | 93 | 260 | 162 |
| USB external hard drive | 1,251 | 136 | 124 |
| SATA hard drive (internal) | 617 | 129 | 118 |
What this says
The typical NVMe drive is five times faster than the typical SATA SSD, not ten. Marketing compares a 7,000 MB/s PCIe 4 drive with a 550 MB/s SATA drive. Users mostly own PCIe 3 and budget PCIe 4 drives, and the median NVMe result is 2,181 MB/s. Still a huge gap, but a gap that only matters for large sequential copies. For a system drive, the SATA SSD to NVMe upgrade is felt far less than the hard drive to SATA SSD upgrade was.
An external SSD over USB is as fast as an internal SATA SSD. 408 MB/s against 435. If your laptop has no free slot, a USB SSD is not a compromise for storage, only for the cable on your desk. The 90th percentile for USB SSDs is 799 MB/s, which is where the 10 Gbps enclosures live; the median is held down by USB 3.0 ports and older enclosures.
Hard drives are hard drives, whichever way you connect them. Internal SATA hard drives and USB external hard drives are within 7 MB/s of each other. The USB bridge is not the bottleneck; the spinning platter is. The slowest 10 percent of external hard drives wrote at 22 MB/s or less, which is the signature of shingled (SMR) drives filling their cache.
Apple's internal SSDs write faster than they read. The Apple silicon drives are the only group in the table where the median write is higher than the median read, by about 25 percent. Every other category reads faster than it writes.
SD cards are faster than external hard drives. 260 MB/s read for a card in a reader against 136 for a portable hard drive. Not what most people expect from the thing that lives in their camera.
Bigger drives are faster drives
Within NVMe, capacity is the strongest predictor of speed we found, more than brand.
| NVMe capacity | Results | Median read | Median write |
|---|---|---|---|
| Under 300 GB | 518 | 1,378 | 916 |
| 300 to 600 GB | 1,575 | 1,876 | 1,406 |
| 600 GB to 1.2 TB | 1,798 | 2,528 | 2,185 |
| 1.2 to 2.5 TB | 1,297 | 2,323 | 2,215 |
| Over 2.5 TB | 217 | 3,591 | 3,428 |
A 256 GB NVMe drive writes at less than half the speed of a 1 TB drive of the same generation. Smaller drives have fewer flash chips to write to in parallel and a smaller cache. If a laptop offers a 256 GB or 512 GB option, this is the difference you are choosing between.
A note on S.M.A.R.T. over USB
35 percent of USB drives on DiskBoard could not report their S.M.A.R.T. health at all (926 of 2,656). Internally connected drives report it almost every time. If drive health matters to you, that is a reason to check an external enclosure's chipset before buying it.
Method
- Source: all DiskBoard uploads at the time of writing, sequential tests only.
- Results above the physical limit of the bus, or with a read more than three times the write, are excluded as RAM-cached. This removes 4 to 9 percent of results depending on the bus.
- "USB flash stick" means a solid-state USB device under 200 GB; "USB external SSD" is 200 GB and above. DiskBoard reads the solid-state flag from the drive.
- Medians throughout.