Skip to main content

Hard Drive Types

There are a few kinds of drives. Spinning disks - either 3.5” @ 7200rpm (faster) or 2.5” @ 5400rmp (slower). Then there are solid state drives (SSDs), there are the 2.5” versions of this (fast) and the NVME version of this (fastest). In addition there are RAIDs, which is a collection of drives in a specific configuration. RAIDs can be made up of all kinds drives, or a mix of drive types. They work best when the drive type is the same IMHO. 

External SSD hard drives that can be USB-C or USB-A run faster R/W with USB-C even if the USB-A port is rated at the same speed as USB-C. This is confusing but tested on MAC and PC with Sandisk Extreme Pro

The interfaces below can communicate with a computer in various ways – directly via PCIE or SATA or through a external enclosure and a secondary interface such as USB or Thunderbolt. 

Hard Drive Type Interface

Max R/W Speed

Sequential

Average R/W Sustained Speeds

Sustained
Spinning Disk Drive 3.5" @ 7200 RPM SATA I/II/III 210 MB/s 85 MB/s
Spinning Disk Drive 2.5" @ 5400 RPM SATA I/II/III 120 MB/s 60 MB/s
Solid State Drive 2.5" SATA III 600 MB/s 450-550 MB/s
Solid State Drive NVMe Gen 3 PCIE 3 3,500/3,000 MB/s

250-1,500 MB/s

Depending on temperature and cache
Solid State Drive NVMe Gen 4 PCIE 4 7,400/6,800 MB/s Haven't used one – theoretical
Solid State Drive NVMe Gen 5 PCIE 5 14,000/10,000 MB/s Haven't used one – theoretical

Format Types

RAIDs

RAIDs are a collection of drives, that when put together, are faster and/or bigger and/or safer. A RAID without any special configuration other than a collective volume is called JBOD ("Just a Bunch of Drives").

RAIDs might have a cache drive that is faster than the rest. Think 4x spinning drives, plus a fifth NVMe. 

RAID Configurations
  1. RAID 0 - also called “striped”, this speeds your drives up considerably, but has zero redundancy. A regular 7200 drives has read/write (“R/W”) speeds of around 120 MB/s. A RAID 0 configuration of 4x 7200 drives has a 700 MB/s R/W. 4x2TB drives = 8TBs.
  2. RAID 1 - also called “mirrored,” this keeps the drives mirrored for redundancy/back-up. The speed is just as fast as a single drive (so 120 MB/s @ 7200). Slower but safer. 4x2TB drives = 4TBs.
  3. RAID 2, 3, 4 - I never use any of these so I couldn’t tell you what they are.
  4. RAID 5 - this is a RAID configuration that gives you speed and parity. Best of both worlds. 4x 7200 drives has a R/W of ~450 MB/s. 4x2TB drives = 6TBs.
Back to top