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HDDs in 2026: CMR vs SMR, and what Windows can still do with spinning disks

Verified 2 min read

Where hard drives still make sense on Windows, how SMR changes write behaviour, and how storage pools and ReFS fit in.

Tested onPro (26H2) / Server · Build 26100.33650 · x64
E1
Build
26100.33650
Edition
Pro (26H2) / Server
Architecture
x64
Support
Documentation (E1)
Evidence
E1Official documentation
Verified
2026-10-29
Page type
Concept

The short answer

Section titled “The short answer”

Hard drives lost the system-disk role and kept three jobs:

  1. Bulk cold storage — media, archives, backups.
  2. Cheap capacity for a NAS or storage pool.
  3. Sequential workloads where cost per TB dominates.

They are bad at random I/O and at anything interactive. On Windows, an HDD as the boot drive is the single biggest perceived-speed downgrade you can choose in 2026.

CMR vs SMR, in one paragraph

Section titled “CMR vs SMR, in one paragraph”
  • CMR (conventional magnetic recording) writes tracks side by side. Predictable performance.
  • SMR (shingled) overlaps tracks to fit more data per platter. Writes that land inside an already-written band require read-modify-write of a whole band, so sustained random writes collapse.

SMR is fine for append-only archives and bad for RAID rebuilds, VM images and active databases. Many consumer drives are SMR without a prominent label; the manufacturer’s datasheet is the only reliable source.

Workload CMR SMR
Media archive (write once) Good Good
Backup target, sequential Good Acceptable
VM disk images Good Poor
RAID rebuild Acceptable Painful
Game installs / unpacking Acceptable Poor

What Windows does with them

Section titled “What Windows does with them”
  • Storage Spaces can pool drives and add redundancy or thin provisioning — see Storage Spaces.
  • ReFS adds integrity streams and block cloning on supported volumes; it is not a boot filesystem for client Windows.
  • NTFS remains the default and is fine for a single drive.
  • Windows Backup / third-party tools handle the backup role; the drive itself does not care.
Terminal window
Get-PhysicalDisk | Select-Object FriendlyName,MediaType,BusType,Size,HealthStatus,SpindleSpeed
Get-Volume | Select-Object DriveLetter,FileSystemType,Size,SizeRemaining

MediaType reports HDD vs SSD, which is enough for pool planning, but not for CMR/SMR — that has to come from the datasheet.

Where an HDD still wins

Section titled “Where an HDD still wins”
  • Cost per TB at 8TB and above.
  • Write endurance for surveillance/archive patterns.
  • Cold data that would waste SSD endurance and money.

Where it loses: anything with random reads (app launch, VM boot, indexing, Windows Update on many small files).

A sane Windows layout

Section titled “A sane Windows layout”
Role Media
Boot + apps NVMe SSD (DRAM or HMB)
Projects/VM images NVMe or SATA SSD
Media/archive HDD, CMR preferred
Backup target HDD or NAS, separate from the source
Scratch/temp SSD (HDD scratch is painful)

Verify before you trust a pool

Section titled “Verify before you trust a pool”
  1. Confirm every drive reports Healthy before adding data.
  2. Fill the pool to ~80% and re-test write speed — SMR and shingled caches fail late, not early.
  3. Run a scrub/verify job if the pool supports it.
  4. Keep a backup: a redundant pool protects against drive failure, not deletion, ransomware or controller failure.
Section titled “Related”

Lab boundary

Section titled “Lab boundary”

E1. Recording technology is a drive property documented by the manufacturer; Windows reports MediaType but not CMR/SMR. No physical HDD was tested for this page.

Sources