Seagate vs WD NAS Drives: Specs Tie, Power Bill Doesn't

Seagate IronWolf Pro and WD Red Pro are sold into the same slot: the NAS drive you buy when the standard tier feels too light. Put their datasheets side by side at 8, 12, 16, 20 and 24TB and the ratings people usually compare turn out to be identical. Three differences are worth choosing on, and they point in different directions.

The verdict

• Warranty, workload rating, bay support, recording method and spindle speed are the same at all five capacities compared here: five years, 550TB a year, unlimited bays, CMR, 7,200 RPM.
• WD Red Pro is lower at idle for every Red Pro model on this page but one, by 1.4W to 3.2W per drive. Over the five-year warranty that is about $11 to $26 of electricity per drive at the U.S. average rate.
• IronWolf Pro includes three years of Seagate’s Rescue data recovery. Western Digital’s Red Pro data sheet lists nothing equivalent.
• At 12TB only, IronWolf Pro carries the higher MTBF rating, 2.5 million hours against 2 million.

So the real question is whether the NAS holds data that exists nowhere else. If you keep a separate backup, the Red Pro’s lower draw is the difference that pays you back. If you do not, Seagate’s Rescue is the one that might — though no recovery service stands in for making that backup.

The exception is 12TB, where the Red Pro name covers two builds and one of them reverses the power result. Buy WD121KFBX, not WD122KFBX.

Check the WD Red Pro 16TB on Amazon↗

What is the same

On Seagate’s IronWolf Pro datasheet (DS2129.4, November 2023) and Western Digital’s Red Pro data sheet (January 2025), every drive compared on this page is rated for:

• 550TB a year of workload
• Five years of limited warranty
• Unlimited drive bays
• CMR recording
• 7,200 RPM

These are the numbers people usually reach for when they compare NAS drives, and at the Pro tier none of them is a reason to prefer one brand.

What is different

1. Idle power

At every capacity compared here, the Red Pro models we list idle lower than the IronWolf Pro at the same size, with one exception:

• 8TB: ST8000NT001 at 7.8W. WD8003FFBX at 4.6W — 3.2W lower. WD8005FFBX at 4.9W — 2.9W lower. All three air-filled.
• 12TB: ST12000NT001 at 5.0W. WD121KFBX, helium-filled, at 2.8W — 2.2W lower. WD122KFBX, air-filled, at 6.1W — 1.1W higher.
• 16TB: ST16000NT001 at 5.0W, WD161KFGX at 3.6W. WD is 1.4W lower.
• 20TB: ST20000NT001 at 5.7W, WD202KFGX at 3.6W. WD is 2.1W lower.
• 24TB: ST24000NT002 at 6.3W. WD241KFGX at 3.6W — 2.7W lower. WD240KFGX at 3.9W — 2.4W lower.

A NAS that stays on around the clock spends most of its time idle, so this is the difference that turns into money. At 18.31¢ per kWh, each watt of continuous draw costs about $8 in electricity over five years. Across four bays, the electricity gap between the two brands over five years comes to about $103 at 8TB, $71 at 12TB, $45 at 16TB, $67 at 20TB and $87 at 24TB, using the lowest-idle Red Pro at each size: WD8003FFBX, WD121KFBX, WD161KFGX, WD202KFGX and WD241KFGX. The power cost calculator will redo those at your own rate.

At 12TB, WD121KFBX and WD122KFBX are both sold as a WD Red Pro 12TB, and they sit on either side of the IronWolf Pro. Our NAS drive guide goes into the two builds sold under that name; for this comparison, the Red Pro only wins at 12TB if you get the helium-filled model number.

The 8TB pair is closer. WD8003FFBX idles 0.3W below WD8005FFBX, but Western Digital lists it higher at read/write (8.8W against 6.9W) and in standby (0.7W against 0.3W). On those figures WD8003FFBX draws less only if the drive is idle more than about 86% of the time, which is roughly three hours or less of read/write a day with no time in standby. If your NAS is busier than that, WD8005FFBX draws less, and time spent in standby, where WD8005FFBX is also lower, narrows the margin further. Both still idle well below the IronWolf Pro 8TB.

The sheets differ on more than idle power: read/write power, standby power and cache size vary too. At read/write, every Red Pro in the table is listed lower than the IronWolf Pro at the same size, with WD122KFBX again the exception. We sort on idle because an always-on NAS spends most of its hours there.

2. Rescue data recovery

Seagate’s datasheet lists three years of Rescue Data Recovery Services for every IronWolf Pro capacity on it. Western Digital’s Red Pro data sheet lists no data recovery service. Seagate notes in a footnote that Rescue is not available in all countries.

Rescue comes with the standard IronWolf too: Seagate’s DS1904.21 datasheet (July 2022) lists the same three years. Neither the Red Pro nor the Red Plus data sheet lists a recovery service, so on paper the difference holds at both tiers.

How much weight it deserves depends on what it does. Seagate describes Rescue as in-house data recovery for accidental data corruption or drive damage. It works after something has gone wrong, and it gives you no second copy of your data. If you keep a separate backup, Rescue covers a situation you have already covered. If the NAS holds the only copy of something, Rescue is the datasheet item most directly aimed at losing it — alongside making a backup, not instead of one.

3. MTBF at 12TB

MTBF is the same at four of the five capacities: 2 million hours for both brands at 8TB, and 2.5 million hours for both at 16, 20 and 24TB. At 12TB, the IronWolf Pro is rated at 2.5 million hours and both 12TB Red Pro builds at 2 million.

MTBF is a statistical rating for a large population of drives, not a prediction for the one in your NAS, so treat this as a small point in the IronWolf Pro’s favor at one capacity rather than a reason on its own.

Compared capacity by capacity

From Seagate's IronWolf Pro datasheet (DS2129.4) and Western Digital's Red Pro data sheet (January 2025), not our own measurements. Every drive here carries a five-year warranty and a 550TB/year workload rating. Running cost is for one drive left spinning at idle for the five-year warranty period. Power cost assumes continuous operation at the U.S. average residential rate, 18.31¢/kWh (EIA, July 2026).

Model	Fill	Idle (W)	MTBF (M hours)	Rescue (yrs)	5-yr power cost
Seagate IronWolf Pro 8TB (ST8000NT001)Seagate	Air	7.8	2	3	$63
WD Red Pro 8TB (WD8003FFBX)Western Digital	Air	4.6	2	—1	$37
WD Red Pro 8TB (WD8005FFBX)Western Digital	Air	4.9	2	—1	$39
Seagate IronWolf Pro 12TB (ST12000NT001)Seagate	Helium	5.0	2.5	3	$40
WD Red Pro 12TB (WD121KFBX)Western Digital	Helium	2.8	2	—1	$22
WD Red Pro 12TB (WD122KFBX)Western Digital	Air	6.1	2	—1	$49
Seagate IronWolf Pro 16TB (ST16000NT001)Seagate	Helium	5.0	2.5	3	$40
WD Red Pro 16TB (WD161KFGX)Western Digital	Helium	3.6	2.5	—1	$29
Seagate IronWolf Pro 20TB (ST20000NT001)Seagate	Helium	5.7	2.5	3	$46
WD Red Pro 20TB (WD202KFGX)Western Digital	Helium	3.6	2.5	—1	$29
Seagate IronWolf Pro 24TB (ST24000NT002)Seagate	Helium	6.3	2.5	3	$51
WD Red Pro 24TB (WD241KFGX)Western Digital	Helium	3.6	2.5	—1	$29
WD Red Pro 24TB (WD240KFGX)Western Digital	Helium	3.9	2.5	—1	$31

Each capacity starts with the Seagate drive, followed by the Western Digital models at that size. Read down the Idle column within each capacity and the pattern is consistent, with WD122KFBX the one drive that breaks it. The Rescue column is the mirror image: filled for every Seagate row, empty for every Western Digital row.

Which one, by what the NAS holds

The column is set by your backup, not by brand. The left column gives the lowest-idle Red Pro model at that capacity among those compared here; the right column gives the IronWolf Pro.

Use case	You keep a separate backup	The NAS holds the only copy
8TB	WD Red Pro 8TB (WD8003FFBX)	Seagate IronWolf Pro 8TB (ST8000NT001)
12TB	WD Red Pro 12TB (WD121KFBX)	Seagate IronWolf Pro 12TB (ST12000NT001)
16TB	WD Red Pro 16TB (WD161KFGX)	Seagate IronWolf Pro 16TB (ST16000NT001)
20TB	WD Red Pro 20TB (WD202KFGX)	Seagate IronWolf Pro 20TB (ST20000NT001)
24TB	WD Red Pro 24TB (WD241KFGX)	Seagate IronWolf Pro 24TB (ST24000NT002)

The columns line up with the brands because the two differences that matter pull in opposite directions. With a separate backup, a failed drive is an inconvenience: you replace it and restore. What remains is five years of electricity, and that favors Western Digital at every capacity here, provided you buy WD121KFBX at 12TB. Without one, a failed drive can mean lost files, and Rescue is the part of either purchase that addresses it. If only some of what the NAS holds is backed up elsewhere, read the right-hand column: a failed drive does not choose which files it takes with it.

Every left-hand cell is a specific model number because Western Digital lists two Red Pro builds at several of these sizes. At 12TB it is WD121KFBX, not WD122KFBX, which would idle higher than the IronWolf Pro it is meant to beat. At 8TB it is WD8003FFBX (4.6W) over WD8005FFBX (4.9W), at 24TB WD241KFGX (3.6W) over WD240KFGX (3.9W), and at 20TB WD202KFGX (3.6W) over WD201KFGX, which the same sheet lists at 3.8W. At 8TB that choice holds only for a lightly used NAS: with more than about three hours of read/write a day, WD8005FFBX draws less (see the 8TB note above).

Who should pick which

Pick WD Red Pro if

• You keep a separate backup of what is on the NAS, so a failed drive is a restore rather than a loss.
• The NAS runs around the clock with four or more drives, where the idle gap multiplies. At 8TB, four WD8003FFBX drives left idling come to about $103 less electricity over five years than four IronWolf Pro 8TB.
• You can check the model number before you buy: WD121KFBX, not WD122KFBX, at 12TB.

Check the WD Red Pro 12TB (WD121KFBX) on Amazon↗

Pick IronWolf Pro if

• Some of what is on the NAS exists nowhere else, and you want a recovery service included with the drive while you sort that out.
• You are buying at 12TB and weigh the 2.5 million-hour MTBF rating against 2 million.

Check the IronWolf Pro 16TB on Amazon↗

What about IronWolf and WD Red Plus?

The standard tiers are a different comparison. They share a 180TB/year workload rating and a three-year warranty, but the datasheets stop at different sizes: Western Digital’s Red Plus data sheet runs to 12TB, while Seagate’s standard IronWolf datasheet (July 2022) runs to 18TB. Rescue comes with the standard IronWolf too.

Our guide to NAS hard drives compares the standard drives model by model on idle power at 8TB and 12TB.

How we compared

Every Pro drive figure on this page comes from two manufacturer datasheets: Seagate’s IronWolf Pro datasheet DS2129.4 (November 2023) and Western Digital’s Red Pro data sheet dated January 2025. The standard-tier capacity ranges come from Seagate’s IronWolf datasheet DS1904.21 (July 2022) and Western Digital’s Red Plus data sheet (September 2025).

These are manufacturer figures, not our own measurements. We have not put a meter on any of these drives.

We compared five capacities — 8, 12, 16, 20 and 24TB — and one Seagate model at each. Both datasheets list more capacities than that, including 10, 14, 18 and 22TB, and we have not compared those. Western Digital’s sheet also lists a second Red Pro build at several sizes. At 8, 12 and 24TB we include both. At 20TB we list WD202KFGX, the lower-idle of the two, and name WD201KFGX in the text. At 16TB the sheet lists one Red Pro. Seagate lists a HAMR-based 24TB IronWolf Pro, ST24000NT031, on a separate datasheet (DS2129.5, April 2024); the 24TB row here is ST24000NT002 from DS2129.4.

So “every Red Pro model on this page” means these five capacities and these model numbers, not the whole of either line. If a listing shows a model number that is not in the table, check it against the maker’s datasheet before assuming the figures carry over.

We have left noise out. Seagate and Western Digital each publish acoustic figures, but under their own conditions, and we do not think the two sets can be compared directly.

Running cost is idle watts × 24 hours × 365 days × 5 years, at 18.31¢/kWh, the U.S. residential average for July 2026 from the Energy Information Administration. Differences in the text are computed from the watt figures, so they can be $1 off from subtracting the rounded values in the table.

Frequently asked questions

Is Seagate or Western Digital more reliable for a NAS?

The datasheets do not settle that, and this page does not try to. On paper the Pro lines carry the same five-year warranty and, at four of the five capacities compared here, the same MTBF rating. We do not use published failure-rate studies here, because the drive models and time periods they cover do not match the current models compared on this page.

Do IronWolf Pro and WD Red Pro work in the same NAS?

Both are rated for unlimited bays on their datasheets, so bay count is not a limit for either. Check your NAS maker’s compatibility list for your specific model.

Is the idle difference big enough to matter?

Per drive, it is modest: the lowest-idle Red Pro at each capacity here is 1.4W to 3.2W below the IronWolf Pro, or about $11 to $26 over five years. The exception is the air-filled WD122KFBX at 12TB, which is 1.1W higher. The gap matters in proportion to how many drives you run and how long they stay spinning. In a four-bay NAS left idling around the clock, it is roughly $45 to $103 in electricity over five years, with WD121KFBX at 12TB.

Which WD Red Pro 12TB should I buy?

WD121KFBX. Western Digital’s data sheet lists it as helium-filled at 2.8W idle, and the air-filled WD122KFBX at 6.1W. Both are sold as a WD Red Pro 12TB, so check the model number on the listing. Our NAS drive guide covers the two builds.

Should I buy Rescue as a substitute for a backup?

No. Rescue tries to get data back after corruption or drive damage. A backup is a second copy that exists before anything goes wrong.