CMR and SMR are methods to store data on hard drives. Each one has a significant part in the storage device performance. SMR stands for Shingled Magnetic Recording, while CMR stands for Conventional Magnetic Recording.
SMR is a relatively new technology that some of the leading manufacturers of hard drives, such as Western Digital and Seagate, have introduced. CMR is an old technology that was first used in the early 90s by many hard drive manufacturers, such as Maxtor and Quantum (now known as Hitachi).
The best way to decide if you should use CMR or SMR on your HDD is to know their differences and apply them to your needs. No technology is perfect, but there is one most suitable for each user’s needs.
But not always the manufacturer adds this information to the driver’s description. Inquire about this information so you can have the best data storage device for your purpose.
For our full breakdown of CMR drive recommendations by use case, see our guide to the best internal hard drives.
Top differences: SMR vs CMR
Both SMR and CMR technologies have their pros and cons, meaning that to choose between them, you need to have a goal and match the technology that best fulfills it.
Speed - CMR
For speed, CMR is the clear winner. It stores data in separate tracks on a CMR hard drive, which allows for much higher data densities. This results in faster data transfer rates and shorter access times. In contrast, data on an SMR hard drive is stored in overlapping tracks. This means that it can have more data stored in an area, but it also slows down data transfer rates and increases access times.
Reliability - SMR
SMR drives are more reliable than CMR drives. Since it stores data in overlapping tracks, there is a lower risk of interruption when reading or writing data. In comparison, this might be an issue with CMR hard drives where the magnetic head can easily hit the edge of the disk and cause damage to it and interrupt the process. This increased reliability is one of the main reasons SMR technology has become popular among enterprise users who require high levels of data integrity and uptime.
Price - CMR
If you have a limited budget and price is a big aspect of your decision, the CMR is at the top of your choice list.
SMRs are more expensive than CMR, since they have different manufacturing costs.
Storage capability - SMR
SMR hard drive stores the data in overlapping tracks. This increases the real density of the disk - the amount of data that can be stored in an area. In contrast, it can easily decrease speed and overflow the cache as you constantly write and rewrite it.
Writing Performance - CMR
With constant writing and rewriting, SMR can have cache overflow. Meanwhile, CMR supports large amounts of data transfer at a high speed. If you have to constantly use your drive or need to change data and access it fast, CMR is then your best choice.
Summary: The type of hard drive you should get - SMR or CMR, depends on your needs and what you’re going to use your drive for. If speed is important to you, then CMR is the better choice. However, if you need a hard drive with higher data capacity, then SMR might be the better option.
Hard Drives brands and models that are CMR or SMR
Which Hard Drives are CMR compatible and which are SMR compatible? Seagate, Toshiba, and WD hard drives have models for each technology.
Here's a complete list that compiles the manufacturers, the HDD's models, and capacities in one place.
| Manufacturer | CMR drive families | SMR drive families |
|---|---|---|
| Western Digital |
WD Red Plus (NAS, 1–14TB) — WD10EFRX, WD20EFZX, WD40EFZX, WD60EFZX, WD80EFZZ, WD101EFBX, WD120EFBX, WD140EFGX WD Red Pro (NAS, 2–22TB) — WD2002FFSX, WD4003FFBX, WD6003FFBX, WD8003FFBX, WD181KFGX, WD221KFGX WD Gold (data center, 1–26TB) — WD1005FBYZ … WD261KRYZ WD Ultrastar DC (enterprise) — HC310, HC320, HC330, HC520, HC530, HC550, HC560, HC570, HC580, HC590 (4–26TB) WD Purple / Purple Pro (surveillance, 1–22TB) WD Blue 3.5" — most current SKUs (250GB–8TB) WD Black 3.5" (500GB–10TB) |
WD Red (non-Plus, NAS) — 2TB / 3TB / 4TB / 6TB: WD20EFAX, WD30EFAX, WD40EFAX, WD60EFAX (DM-SMR; basis of the 2020 class action) WD Blue 2.5" — 1TB (WD10SPZX), 2TB (WD20SPZX) WD Blue 3.5" — 2TB (WD20EZAZ), 6TB (WD60EZAZ) WD Black 2.5" — 1TB (WD10SPSX) WD Elements / My Passport 2.5" portable (1–5TB) |
| Seagate |
IronWolf (NAS, 1–12TB) — ST1000VN002 … ST12000VN0008 IronWolf Pro (NAS Pro, 4–32TB) — ST4000NE001 … ST32000NT000 Exos X / Exos M (data center, 2–32TB) — Exos 7E8, X10, X12, X14, X16, X18, X20, X22, X24, X32 (Mozaic 3+ HAMR) SkyHawk (surveillance, 1–10TB) — ST1000VX005 … ST10000VE0008 SkyHawk AI (8–32TB) BarraCuda Pro 3.5" (2–14TB, legacy) FireCuda 3.5" SSHD (1–2TB) Constellation ES (legacy enterprise, 1–4TB) |
BarraCuda 2.5" — all current SKUs (1–5TB): ST1000LM048/049, ST2000LM015, ST3000LM024, ST4000LM024, ST5000LM000. Seagate has confirmed all 2.5" drives shipped since 2021 are SMR. BarraCuda 3.5" — ST2000DM008, ST3000DM007, ST4000DM004, ST5000DM000, ST6000DM003, ST8000DM004 SkyHawk 2.5" / Lite — 1TB, 2TB Archive HDD (5/6/8TB, discontinued) Backup Plus, Expansion Portable, One Touch, Game Drive — most 2.5" portable externals |
| Toshiba |
N300 (NAS, 4–22TB) X300 (performance, 4–22TB) — MD07ACA / MD08ACA base MG07 / MG08 / MG09 / MG10 (enterprise, 6–24TB) MD04 / MD05 / MD06 (enterprise, 2–6TB) S300 (surveillance, 4–10TB) DT01ACA (older P300 base, 500GB–3TB) MQ01ABF / MQ01ABU (2.5" mobile, up to 500GB) V300 (surveillance, 2–3TB) |
P300 — 4TB (HDWD240), 6TB (HDWD260) DT02 — 2TB (7200rpm), 4TB (DT02ABA400), 6TB (DT02ABA600) DT02-V — 4TB, 6TB (surveillance variant) L200 — 1TB (HDWL110), 2TB (HDWL120) MQ04 — 1TB (MQ04ABF100), 2TB (MQ04ABD200) |
| HGST / Hitachi |
Deskstar NAS, Ultrastar He / Hs / DC HC series — all CMR (now sold under WD Ultrastar branding since the HGST brand was retired around 2018). |
Travelstar Z5K1 500GB (2.5" DM-SMR) |
| Samsung |
Legacy SpinPoint and EcoGreen series — all CMR. Samsung exited the HDD business in 2011 (sold to Seagate); no current production. |
None — left the market before DM-SMR shipped widely. |
| LaCie |
2big RAID, 12big, d2 Professional, 1big Dock — desktop externals using Seagate IronWolf / IronWolf Pro mechanisms. |
Mobile Drive, Rugged 2.5" portable — Seagate BarraCuda 2.5" mechanisms. |
| Dell EMC / HPE |
OEM-rebranded enterprise drives sourced from Seagate, WD, and Toshiba. Almost all are CMR (data-center workloads). Identify the underlying mechanism by the Seagate/WD/Toshiba model number on the label. |
Not used in enterprise OEM SKUs. |
Note: SMR vs. CMR can vary within a family by exact model number — always confirm via the full model number on the drive label, not by family name alone. The classic example is the WD Red 6TB: WD60EFRX (64MB cache) is CMR, while WD60EFAX (256MB cache) is SMR.
When it comes to data storage, it is important to always have a data recovery plan.
Keep a regular backup of your important files to guarantee you can always have access to them. If anything happens to your data, contact one of the SalvageData experts who will promptly help you get your data back.