Enterprise hard drives
The highest capacities in the corpus, and the lowest price per terabyte in it.
Enterprise drives carry the longest warranties, the highest rated workloads and the largest caches here, and because they are sold in the largest capacities they also work out cheapest per terabyte. What they are not is quiet or cool, which is why they belong in a cupboard or a rack rather than under a desk.
What an ordinary enterprise drive looks like
| Capacity | 12 TB |
| Spindle speed | 7,200 RPM |
| Cache | 256 MB |
| Price per terabyte | under $40 per TB |
Medians, with values beyond 1.5× the interquartile range excluded so one listing cannot move them. A class holding fewer than 8 drives publishes no baseline at all.
How this class is distributed
48 drives in this corpus sit in this class. By capacity:
| Under 2 TB | 1 |
| 2 TB to 4 TB | 6 |
| 4 TB to 8 TB | 9 |
| 8 TB to 14 TB | 10 |
| 14 TB and above | 22 |
Why the most expensive drives are the cheapest storage
Enterprise drives carry the highest prices per unit in this corpus and the lowest price per terabyte in it, and both facts follow from the same cause: they are sold in the largest capacities available. Price per terabyte falls as capacity rises across the whole corpus, and enterprise drives sit at the top of that curve. A buyer comparing sticker prices concludes these are the expensive option; a buyer comparing cost per terabyte stored reaches the opposite conclusion, and only one of those comparisons describes what the storage costs.
What the workload rating is for
Enterprise drives are rated for the highest annual workloads here and carry the longest warranties in the corpus. That combination is the product: not that the drive is faster in any way you would notice, but that the manufacturer will underwrite far more use of it for far longer. For a drive that will be written to continuously for years, the rating is a more useful number than any speed on the listing.
Noise, heat and where they belong
These are the loudest and hottest drives here, and neither figure appears on most listings. A rack or a cupboard absorbs both; a desk does not. The frequent mistake is buying enterprise drives for a machine that sits beside someone, discovering the noise is not a defect, and finding that the price per terabyte that justified the purchase does not compensate for it. Where the machine is in the same room as a person, a NAS drive is usually the better trade even though it costs more per terabyte.
SAS is not a bonus
A minority of enterprise drives here use a SAS interface rather than SATA. SAS drives will not connect to an ordinary motherboard without a host bus adapter, and a listing rarely makes that obvious. A SAS drive bought by mistake is not a slower drive; it is a drive that does not work in the machine at all until more hardware arrives. Check the interface before the capacity.
Recertified and renewed listings
Roughly one listing in seven here is sold as recertified, renewed or manufacturer-refurbished. These are drives that have been returned or pulled from service, tested and resold, and they are usually the cheapest per terabyte on the page. What changes is the warranty — often months rather than years — and what is not disclosed is the hours already on the drive. For storage where the data exists elsewhere, the arithmetic can be sound. For the only copy of anything, buying a drive with an unknown history to save a fraction of its price is a poor trade, and the price per terabyte on this page does not distinguish between the two.
Shingled recording, and the word that is missing
Drives record in one of two ways. Conventional recording writes tracks side by side; shingled recording overlaps them like roof tiles to fit more on a platter, which makes rewriting a track require rewriting its neighbours. On sustained writes a shingled drive can slow to a fraction of its rated speed once its cache fills, and in a RAID rebuild that can turn hours into days. The tell is what listings choose to say: in this corpus the term CMR appears roughly twenty times more often than SMR, because conventional recording is advertised as a feature and shingled recording is simply not mentioned. Silence is not evidence of either, but a drive that makes a point of saying CMR is telling you something a drive that says nothing is not.
Why the capacity you get is smaller than the one you bought
Drive manufacturers count a terabyte as a trillion bytes; operating systems generally count it as 2^40, about ten per cent more. A 4 TB drive therefore shows as roughly 3.63 TB before a single file is written, and nothing is wrong. Formatting and the file system take a further small share. This is not a specification any listing states and it is the most common reason a new drive appears to have arrived short, so it is worth expecting rather than discovering.
Power drawn for a decade is a real number
These drives spin continuously and draw more than any other class here, and the cost is paid every hour for the life of the array rather than once at purchase. Over years of uninterrupted operation the electricity can approach a meaningful fraction of what the drive cost, which is worth including when comparing four small drives against one large one. Fewer, larger drives win twice: lower price per terabyte at purchase, and fewer motors running afterwards. That is the same arithmetic the price-per-terabyte curve describes, arriving from the other direction.
The warranty is the longest here, and it is part of the product
Enterprise drives carry the longest warranties in this corpus by a clear margin — several years where an external drive typically gets one. That is not incidental packaging. A manufacturer offering five years on a drive it expects to run continuously is making a costed statement about the failure rate it anticipates, and it is the most honest durability figure on any listing, because it is the only one the manufacturer has to pay for if it is wrong. Compare it directly against the warranty on the class you are considering instead, and the price gap between them starts to look different.
Reading these figures
Every number above is a median of what manufacturers publish, not a measurement we took. Where a specification is missing from this table it is because too few listings in the class stated it for a median to mean anything — that is a fact about the listings, not about the drives.
Narrow this class by capacity and budget in the hard drive finder.