Seagate SkyHawk Prices - AI vs Standard, Live

Two tiers, and the part number is what tells you which you are buying

SkyHawk is sold as one brand and is really two products. Seagate's datasheets rate the standard SkyHawk line for always-on workloads of 180TB per year and cover it with a three-year limited warranty. SkyHawk AI is rated at 550TB per year with a five-year limited warranty, carries 32 AI channels, and reaches capacities the standard line never approaches. Those are the manufacturer's own figures, taken from the datasheet for each part number rather than from a line summary, and the gap between the two tiers is larger than the shared name suggests.

The name on the box is not a reliable guide to which tier a listing belongs to, because sellers write their own titles. The part number is. Standard SkyHawk parts follow the ST<capacity>VX pattern; SkyHawk AI parts follow ST<capacity>VE. One letter separates a 180TB-per-year drive from a 550TB-per-year one, and a listing headline that says only "Seagate SkyHawk surveillance" tells you nothing about which you are about to receive. The decoder table above is built from the part numbers we actually track, so it maps the pattern to the tier rather than describing the tiers in the abstract.

Western Digital splits its surveillance range the same way and with the same trap. WD Purple is rated at 180TB per year with a three-year warranty; WD Purple Pro is rated at 550TB per year with a five-year warranty and 32 AI streams. The part-number tell is the suffix: PURZ or PURX for the standard line, PURP for Pro. Two drives of the same capacity from the same brand, sitting next to each other in search results, can carry ratings that differ by a factor of three.

This matters more in surveillance than in almost any other category, because a recorder writes continuously by definition. A drive in a desktop is idle most of the day. A drive in a four-camera NVR is writing every second the system is powered, which is the workload figure's entire subject. Buying the lower tier is a legitimate decision when the camera count is small; buying it without knowing that is what the tier decoder exists to prevent.

The one thing to check before you buy: recording technology, per part number

Shingled magnetic recording overlaps data tracks like roof tiles to raise density. Reading is unaffected. Writing is affected when the drive has to modify data underneath an existing track, because the tracks laid over it may have to be rewritten too. A surveillance recorder does one thing forever: it writes, and once the disk fills, it overwrites the oldest footage in a continuous loop. That loop is close to the worst-case pattern for shingled recording, and it never stops to let the drive catch up.

Seagate's own SkyHawk datasheet states SMR against ST4000VX013 in the same column block where the other 4TB part, ST4000VX007, is stated as CMR. Seagate's SkyHawk SATA product manual for that generation repeats it in section 2.4, giving the recording method for the ST2000VX015 and ST4000VX013 family as SMR. Two Seagate documents, agreeing, at part-number resolution. Those models are in stock and they sit in search results beside conventionally-recorded SkyHawk drives of the same capacity under names that do not distinguish them.

Seagate also publishes a CMR and SMR list that states recording technology by capacity rather than by part number, and that list shows no SMR anywhere in the SkyHawk line. We are not going to resolve that disagreement between two Seagate publications, and we are not going to quietly pick the answer that makes a cleaner table. What we can do is show you which document says what, badge the specific part numbers the datasheet and manual name, and link both sources so you can read them yourself. The block above lists every shingled model we currently have in stock.

For Western Digital the situation is cleaner but incomplete. The current WD Purple data sheet and product brief state CMR explicitly for the current PURZ generation, and the Purple Pro brief states CMR for the models it covers. The previous-generation WD Purple data sheet prints no recording-technology row at all, so those part numbers carry no technology claim from us and show as unverified. That produces a table with visible gaps, which is the correct outcome: an inferred specification printed in a table looks exactly like a sourced one to whoever is reading it.

The practical instruction is short. Read the badge on the exact row you are buying, not the badge on the line, and treat unverified as unverified rather than as probably fine. Our CMR versus SMR lookup carries both surveillance lines alongside every other brand we track.

What the current lineup actually reaches

A great deal of surveillance drive advice online was written against a lineup that no longer exists, and the most common stale claim is a capacity ceiling. Guides still describe SkyHawk as topping out in the region of 10TB. Seagate's current SkyHawk AI datasheet covers 20TB, 24TB and 32TB part numbers, and its published recording-technology list places the 32TB SkyHawk AI under Mozaic HAMR CMR. The line reaches 32TB today, and we have a 32TB SkyHawk AI in stock and priced in the table above.

The same drift affects the Purple range. The current WD Purple product brief describes the standard line as reaching 8TB, while the Purple Pro brief describes capacities up to 26TB. Guides that treat Purple as a single 1TB-to-14TB range are describing a mixture of two generations and two tiers that no longer maps onto what is on sale.

This matters beyond pedantry, because a stale ceiling changes an actual buying decision. If you believe the largest surveillance drive available is 10TB, a project needing long retention across many cameras looks like it requires several drives and therefore a larger recorder. If the real ceiling is 32TB, the same project may fit in the bays you already have. The number of bays a system needs is downstream of the largest drive that exists, so a wrong ceiling propagates into a wrong hardware plan.

Our tables solve this by not containing a lineup at all. They contain the listings that were in stock when the page loaded, with the capacity each one actually is. A capacity disappears from this page when nobody is selling it and appears when somebody is, which is a different thing from a published range and a more useful one when you are buying today rather than describing a product family.

How long a drive records, and why that is arithmetic rather than a promise

The question every surveillance buyer actually has is how many days of footage a given drive holds, and it is answerable, but only as an estimate with its inputs stated. The arithmetic is simple: a terabyte is a million megabytes, a bitrate in megabits per second divided by eight gives megabytes per second, and dividing one by the other gives seconds of recording which divide down into days. The estimate table above runs that calculation across the capacities we have in stock at four example bitrates, and prints the formula underneath so you can redo it with your own number.

What makes it an estimate rather than a specification is the bitrate. A camera's rate depends on its resolution, its codec, its frame rate and how much movement is in frame, and most cameras are configured with variable bitrate, meaning the rate rises when something moves and falls when nothing does. A car park at night and a busy shop floor at midday can differ by several times on the same hardware. Anyone publishing a single confident retention figure for a drive is quietly assuming a bitrate they have not told you.

The way to use the table is to find your own number first. Most recorders display the current bitrate per channel somewhere in their status screens, and multiplying that by your camera count gives the aggregate rate the drive sees. Run the arithmetic on that and you get a retention figure grounded in your system rather than in an assumption about it. Then subtract a margin, because recorders reserve space and because motion-triggered recording is bursty.

One structural point often missed: retention scales linearly with capacity but the cost per terabyte usually does not. Because the larger drive is frequently cheaper per terabyte, doubling capacity to double retention often costs considerably less than double. The $/TB column in the tables above is where that shows up, and it is the reason the capacity-jump check is worth running before settling on a size.

SkyHawk Health Management and WDDA, described only as far as the docs go

Both makers ship a drive-health feature aimed at recorders, and both are routinely overdescribed in third-party guides. We will state what the documents state and stop there.

Seagate's SkyHawk datasheets describe SkyHawk Health Management as focusing on prevention, intervention and recovery options, and mark per model whether it is included, which is why our decoder shows it as a per-part-number field rather than a line feature. The same datasheets state that RAID RapidRebuild is included. Seagate's documentation notes that further information on the health-management feature comes through a Seagate sales representative, which is a fair signal that the deployment details are not fully public.

Western Digital describes WDDA, Western Digital Device Analytics, on the Purple Pro brief as monitoring drive health and recommending action to improve drive operation, and states plainly that it requires a compatible video recorder or system. That last clause is the one that matters and the one usually dropped in summaries: the feature is a partnership between the drive and the recorder, not something the drive delivers on its own.

What neither maker publishes, and what we therefore will not repeat, is a list of which specific NVR brands and firmware versions surface these features. Claims of that kind circulate widely and we could not source any of them. If the health feature is a deciding factor in your purchase, the reliable check is your recorder's own documentation or its support line, not a drive datasheet and certainly not a third-party article. Our drive health section covers what SMART attributes you can read yourself regardless of whether the recorder supports the vendor feature.

Surveillance drives in a NAS, and NAS drives in a recorder

Both crossings are asked constantly, and they have different answers, which is why the usual blanket advice satisfies nobody.

Taking a SkyHawk or a Purple and putting it in a NAS is the weaker idea. These lines are tuned for a specific duty cycle: many sequential write streams, continuous, with reads only when somebody reviews footage. A NAS does something else, mixing random reads and writes with parity operations and rebuild traffic. The drives will function, but you are buying a specialisation you will not use, and at the standard tier you are buying a 180TB-per-year workload rating for a machine whose workload is harder to predict. If the box is a NAS, buy a NAS line — our IronWolf hub and NAS hard drives cover what is in stock and at what rate.

The reverse crossing is more reasonable than its reputation. An IronWolf or a Red in a recorder is not a mistake in the way a shingled desktop drive would be. NAS lines are conventionally recorded, rated for continuous operation and warranted accordingly, and a recorder's continuous sequential write is well within what they are built to absorb. What you give up is the surveillance firmware behaviour: the frame-handling tuning both makers advertise for multi-stream video, and the health-management integration if your recorder supports it. Whether that is worth anything depends on your recorder.

The honest decision rule is the workload figure rather than the marketing category. Multiply your camera count by your typical per-camera bitrate, convert to terabytes per year, and compare it with the rating printed against the exact part number in the tables above. A four-camera home system at moderate bitrate lands nowhere near 180TB per year, and at that point the choice between tiers is about warranty and capacity rather than about headroom. A thirty-camera installation is a different calculation and is precisely the case the AI and Pro tiers exist for.

One thing that is not negotiable in either direction: recording technology. A shingled drive is wrong for a recorder and wrong for an array, and no amount of firmware tuning on either side changes what happens when a continuous write meets an overlapping track.

Who buys which tier, in plain terms

A home system with four to eight cameras, recording to a consumer recorder from Hikvision, Dahua, Reolink or a similar vendor, is comfortably inside what the standard tier is rated for. The right purchase is usually the largest standard-tier drive with a good cost per terabyte and a conventionally-recorded badge, and the money saved against the AI tier buys retention instead of headroom. Check the recording badge and the capacity against your recorder's supported maximum, and that is the decision.

An installer filling a sixteen or thirty-two channel recorder is in a different position. The aggregate write rate is several times higher, the system runs unattended in a cabinet where nobody notices a degraded drive for months, and the labour cost of returning to site dwarfs the price difference between tiers. The higher workload rating and longer warranty are cheap in that context, and the capacity ceiling of the AI and Pro tiers is often the deciding factor by itself.

Anyone running analytics on the recorder rather than on the cameras sits in the case both makers designed the top tiers around: video is written while previously-written video is read back for analysis, so the drive is doing two things at once instead of one. Seagate states 32 AI channels for SkyHawk AI and Western Digital states 32 AI streams for Purple Pro, both under their own testing conditions. Those figures are theirs, reproduced as published, and they are the closest thing to a sizing guide either maker offers.

The case for a mixed system deserves naming, because it is common and sensible. Nothing stops you running a larger AI or Pro drive as the main recording target alongside a standard-tier drive for overflow or for a second, lower-priority group of cameras. Recorders generally handle mixed capacities better than parity arrays do, since footage is written per volume rather than striped with parity. The deals page checks each drive against its own tracked price history, which is the tool for buying the pieces of a mixed system at sensible moments rather than all at once.

What we deliberately do not tell you

Surveillance drive comparisons are unusually full of confident numbers with nothing behind them: percentage improvements in write performance, failure-rate reductions, and precise camera counts attributed to nobody. We publish none of that, and the omission is deliberate rather than an oversight.

Every specification on this page came from the maker's own datasheet for that exact part number, and the source is linked on the row. Where a datasheet did not state a field, the cell is a dash. Where two of a maker's own documents disagree, we show both and say so rather than choosing. Where a figure is the maker's own claim rather than a measurement — camera counts, AI channels, workload rates — it is attributed to them and reproduced in their terms.

We also do not compare these drives on speed, and we do not carry a benchmark table. A recorder's constraint is sustained sequential write and the network in front of it, and the differences that get quoted between surveillance models rarely come from a documented test at all. Publishing a number we cannot source would make this page look more authoritative and be worth less, which is a bad trade.

What we do have that a static article cannot is the price. Every figure in the tables above was in stock when the page loaded, refreshed every few hours, with the condition of the listing badged and out-of-stock rows excluded from the rankings entirely. The specifications are the makers'; the prices and the arithmetic on them are ours.

Frequently asked questions

Sources

Specification claims on this page were checked against the pages below on 4 August 2026. Where a widely-repeated figure did not survive that check, we report what the source says now and say so in the text rather than repeating the familiar number.

1. Seagate Technology — SkyHawk 3.5in HDD data sheet (DS1902-16) (Seagate.com, 2021)
   Used for: per-part-number recording technology (ST4000VX013 stated as SMR while ST4000VX007 is stated as CMR), cache size per model, 180TB/year workload rate limit, 3-year limited warranty, up to 64 cameras supported, SkyHawk Health Management inclusion per model
2. Seagate Technology — SkyHawk 3.5in HDD data sheet (DS2118-1) (Seagate.com, 2022)
   Used for: ST8000VX010 and ST6000VX009 stated as CMR, 256MB cache, 180TB/year, 3-year warranty
3. Seagate Technology — SkyHawk SATA Product Manual, Rev. A (100870481) (Seagate.com, 2020)
   Used for: section 2.4 Recording and interface technology states the recording method for the ST2000VX015 / ST4000VX013 generation as SMR
4. Seagate Technology — SkyHawk AI data sheet (DS1960-15C) (Seagate.com, 2023)
   Used for: 32TB, 24TB and 20TB SkyHawk AI part numbers, CMR, helium design, 32 AI channels, up to 64 HD cameras supported, 550TB/year workload rate limit, 5-year limited warranty, cache per model
5. Seagate Technology — SkyHawk AI data sheet (DS1960-13C) (Seagate.com, 2022)
   Used for: 10TB to 20TB SkyHawk AI part numbers, CMR, 256MB cache, 550TB/year, 5-year warranty, RV sensors
6. Seagate Technology — CMR and SMR hard drive list (Seagate.com, 2026)
   Used for: capacity-level recording technology for SkyHawk and SkyHawk AI, including 32TB SkyHawk AI listed under Mozaic HAMR CMR. Stated by capacity, not by part number, and it does not reproduce the SMR entry that appears in Seagate's own SkyHawk datasheet and product manual
7. Western Digital — WD Purple surveillance hard drive data sheet (WesternDigital.com, 2025)
   Used for: current-generation PURZ model numbers stated as CMR, cache per model, 180TB/year annualized workload rating, 3-year limited warranty, up to 64 HD cameras
8. Western Digital — WD Purple HDD product brief (WesternDigital.com, 2024)
   Used for: capacity up to 8TB on the current WD Purple line, WD11PURZ / WD23PURZ / WD33PURZ stated as CMR, 180TB/year, 3-year limited warranty, up to 16 drive bays
9. Western Digital — WD Purple series data sheet (previous generation) (WesternDigital.com, 2020)
   Used for: per-model annualized workload rating showing 360TB/year on WD82PURZ, WD101PURZ and WD121PURZ against 180TB/year on the rest of that generation; performance class 7200 RPM vs 5400 RPM per model; this sheet prints no recording-technology row, so those models carry no tech claim from us
10. Western Digital — WD Purple Pro smart video hard drive product brief (WesternDigital.com, 2025)
    Used for: capacity up to 26TB, WD260PURP / WD241PURP / WD221PURP / WD181PURP stated as CMR at 7200 RPM with 512MB cache, 550TB/year annualized workload rating, 5-year limited warranty, 32 AI streams, up to 64 HD cameras, WDDA health monitoring
11. DatacenterDisk Research — Live surveillance drive price and stock database (DatacenterDisk.com, Live)
    Used for: every price, $/TB figure, stock state, condition badge and price-history range on these pages
12. DatacenterDisk Research — CMR vs SMR — which drives are which (DatacenterDisk.com, 2026)
    Used for: cross-brand recording-technology lookup, including both surveillance lines