Vendor notes
How vendors report S.M.A.R.T. differently
The underlying signals are physical: sectors, hours, heat, wear. The labels are not. A field that means reallocated sectors on a Seagate drive can sit under a different ID on a Toshiba MG Series, and SSD vendors often replace surface-error logic with endurance logic. This page explains how each vendor's mapping works and what to watch for in their drive families.
Seagate and WD: the mainstream comparison
Seagate and WD share most attribute IDs, which makes them the easiest pair to reason about side by side. Both expose reallocated sectors, pending sectors, and temperature under familiar numbers. WD Blue is the common consumer reference for desktop HDD health checks, interpreted with general failure markers rather than enterprise metrics.
Differences show up more in labeling than in meaning. Seagate documentation groups its attributes by drive family, so a Seagate SMART attribute list for an IronWolf disk and one for a BarraCuda read almost identically — the wording around workload and power-on hours is where they part ways. WD Blue SMART readings follow the same ID conventions, but WD's guidance leans on the conditions a desktop drive actually meets: a few hours a day, warm case air, and long idle periods.
Look up a S.M.A.R.T. attributeThe pair you can read side by side
Reallocated sectors
Same field on both vendors' consumer lines. Read it as a count that should stay quiet — a value that only climbs is the part worth attention, not the single snapshot.
Pending sectors
Seagate and WD both surface this as unstable sectors waiting on a read attempt. The number moving after a full surface scan is more telling than the number itself.
Temperature
Reported plainly. Desktop enclosures breathe better than laptops, so compare each drive against its own case, not against a number borrowed from another machine.
A sector counter means one thing. A wear counter means another. The mapping tables make that difference visible.
Western Digital Ultrastar: enterprise framing
Ultrastar is WD's enterprise drive family. Enterprise HDDs are monitored in server environments where uptime is the priority, so the same S.M.A.R.T. attributes are read as an operational maintenance signal rather than a home-PC warning. Workload ratings and durability expectations matter alongside the counters. The values are familiar; the tolerance and the consequences are not.
What changes
The attributes do not move, but the reading does. In a tape-library or storage-array chassis, a small counter change is a maintenance ticket before it is a failure. In a home tower, the same counter is often left alone until the drive starts making noise.
What to watch
Whether the workload the drive was rated for matches the workload it is actually carrying. An Ultrastar kept for light desktop duty is fine to read the same way you read a WD Blue — but the tolerance band you accept before acting is narrower in a 24/7 job.
Where to look
WD's own datasheets list workload and endurance for each Ultrastar model. Pair those numbers with the live counters your monitoring tool reports; neither alone tells the whole story.
If you are matching an Ultrastar reading against the general database, open the full attribute database and filter by the vendor rather than by the ID alone — the same number is not always the same meaning.
Toshiba: N300 and MG Series
Toshiba's N300 is the NAS-focused line, built for always-on use in home or small-office arrays. That changes how you read power-on hours: continuous operation is the design, not a red flag. Vibration and temperature control matter more in NAS use because array health depends on early warning from every drive. The MG Series occasionally maps fields differently from consumer Toshiba drives, so confirm the ID before you interpret it.
N300 — always-on reading
Long power-on hours are the expected shape of this line's life. Watch the counters that track vibration and temperature instead, because those are the ones that shift when an array is unhappy before a drive fails outright.
MG Series — confirm the ID
Toshiba MG Series drives occasionally map a field to a different ID than their consumer siblings. Before trusting a table row, check the field name against the drive family you actually have in hand.
Samsung: Magician as a shortcut
Samsung Magician is Samsung's SSD management tool. It monitors health, updates firmware, and manages optimization features, which means non-technical owners often never see the raw attribute table at all. That is a fair trade for most people.
The 870 EVO, a mainstream SATA line, exposes wear-related metrics rather than bad-sector style readings, so the vocabulary is different from HDD diagnostics. When someone says their SSD health "went down," they are usually reading a life-left figure, not a pending-sector count — and those describe different things.
Endurance logic, not surface errors
NAND has no rotating platters and no head flying over a surface. That is why an SSD lifecycle is described in writes and wear cells rather than in bad sectors. A Samsung drive reporting a healthy wear figure and a Samsung drive reporting high writes used are two different stories, even when both show the same remaining-life percentage.
Kingston and Crucial: SSD endurance logic
Crucial publishes SSD-specific S.M.A.R.T. guidance and documents endurance-style metrics such as remaining-life indicators. Crucially, Crucial frames SSD health separately from classic HDD surface-error logic, which is the correct mental model. Kingston reports through its own ID ranges. Both vendors reward the same habit: read the wear indicator, not the bad-sector counter, because the latter barely applies to NAND.
Kingston — its own ID ranges
Kingston does not simply reuse a generic SSD template. Its drives can report wear and health through ID ranges that differ from the HDD set, so a straight numeric comparison between a Kingston SSD and a mechanical drive is not a fair one.
Crucial — remaining-life indicators
Crucial's documentation treats remaining life as the headline figure for an SSD, which is why a Crucial MX500 health reading is closer to a fuel gauge than to a fault log. Track the trend, not the single value.
The habit both reward
Read the wear indicator, because NAND failure is a long, gradual story. A bad-sector count on an SSD is usually a leftover field, not a meaningful signal, so weight it accordingly.
Comparing the same problem across vendors
A single failing NAND block on an SSD looks nothing like a reallocated sector on an HDD, even though both reduce spare capacity. The mapping tables make that difference visible. When comparing drives, compare like-for-like readings, not attribute IDs that happen to share a number.
| Vendor family | How the reading is framed | What to watch first |
|---|---|---|
| Seagate consumer | Classic HDD surface logic under familiar IDs | Reallocated and pending sectors, plus temperature |
| WD Blue | Desktop HDD health checks with general failure markers | Sector counters, then how the enclosure breathes |
| WD Ultrastar | The same attributes read as a maintenance signal | Counters next to the model's workload rating |
| Toshiba N300 | Always-on NAS duty, so long hours are normal | Temperature and vibration in the array |
| Toshiba MG Series | Enterprise Toshiba mapping, occasionally differs | Confirm which field sits under which ID |
| Samsung SSDs | Wear-related metrics read through Magician | Life-left trend, and firmware updates |
| Kingston SSDs | Vendor ID ranges for wear and health | The wear field, not the bad-sector field |
| Crucial SSDs | Endurance framing with remaining-life figures | How fast the remaining-life figure moves |
A practical checklist per vendor
Use these as a first pass. For Seagate and WD consumer drives: watch the reallocated-sector and pending-sector counters, then temperature. For Ultrastar: read attributes alongside workload expectations. For Toshiba N300: treat continuous hours as normal and watch temperature. For Samsung and Kingston SSDs: track wear level and life left. For Crucial SSDs: use Crucial's endurance framing. The database holds the specifics.
Seagate and WD consumer drives
Watch the reallocated-sector count (ID 05 on most consumer drives), the pending-sector count, and temperature. A stable reallocated figure that does not move across several scans is less worrying than one that ticks upward every week.
Western Digital Ultrastar
Read the counters against the model's rated workload. A small counter change that would be a shrug in a desktop tower is a maintenance ticket in a 24/7 array, so resolve the tolerance before you rely on a single reading.
Toshiba N300
Treat long power-on hours as normal for this line and focus on temperature and vibration first. In a NAS enclosure, one drive running warm is worth checking even when its own counters look clean.
Samsung and Kingston SSDs
Track wear level and life left, not a bad-sector counter. If the life-left figure is falling faster than the amount of data you are writing would explain, check the firmware version before assuming the drive is on its way out.
Crucial SSDs
Use Crucial's endurance framing: remaining life is the figure that matters, and its trend over time says more than one snapshot. If you are checking a used drive before buying it, compare the remaining life against the age the seller reports.
Why the mapping changes
Vendors extend the standard attribute set for firmware and product needs. That is why some IDs mean different things on different drives, and why this site labels vendor-specific fields rather than guessing. When a definition is genuinely ambiguous, it is marked that way.
The three guides below cover the practical questions a manufacturer's naming difference ultimately raises: is this drive dying, is this used SSD worth buying, and is this temperature actually a problem. Read them alongside the attribute tables so you always know whether you are looking at a surface-error signal or a wear signal.
How to tell a drive is dying
The counters and habits that actually signal the end of a drive's useful life.
How to check a used SSD before buying
What to read from a seller's drive data and what questions to ask first.
Why 60°C is a problem
Why sustained high temperature matters more than a single hot reading.
Two vocabulary systems
A mechanical drive fails by losing usable surface. An SSD fails by exhausting cells. Everything a manufacturer prints on a box, and everything its tool reports, follows from that difference — which is why one set of labels will not describe both.
One reference, six vendor families
The database holds the vendor-specific field names, the general IDs, and the threshold notes that go with each. If a mapping looks wrong or a field is missing, tell us — that is how the reference stays useful.