DatacenterDisk

MDD 20TB vs WD Ultrastar

Side-by-side spec and price comparison. Live data from Amazon US.

+ Add driveShare comparison
Our Recommendation
👑
MDD 20TB SATA 7200RPM NAS

MDD 20TB SATA 7200RPM NAS wins on both price ($27.00/TB) and warranty (5 years).

Best $/TB: MDD
Best Warranty: MDD
Best for RAID: MDD
Full Specification Comparison
Spec
MDD
20TB SATA 7200RPM NAS
$27.00/TB
WD
Ultrastar 20TB SATA
$28.00/TB
Brand
MDD
WD
Model
20TB SATA 7200RPM NAS
Ultrastar 20TB SATA
Series
MDD Enterprise
Ultrastar
Part Number
MD20TS25672NAS
—
$/TB
👑$27.00
$28.00
Price
$539.99
$559.99
Condition
New
Refurb
Capacity
20TB
20TB
Interface
SATA-6G
SATA-6G
Form Factor
3.5"
3.5"
Drive Type
HDD
HDD
Recording Tech
CMR
CMR
RPM
7,200
7,200
Cache
256MB
512MB
Sector Size
512e
—
Workload Rating
550TB/yr
—
DWPD
N/A
N/A
Warranty
5 years
—
Workload Tier
nearline
nearline
In Stock
✓ In Stock
✓ In Stock
Buy
Buy on Amazon →
Buy on Amazon →
Workload Fit
Workload
MDD
WD
NAS Storage
●●●
●●●
Backup Target
●●●
●●●
OLTP Database
●
●
Cold Archive
●●●
●●●
Virtualization
●
●
AI/ML Storage
●●
●●
Buying Recommendation
Choose MDD 20TB SATA 7200RPM NAS if:
  • ✓ You need maximum storage per dollar
  • ✓ You need 5-year warranty coverage for production
  • ✓ You're building a RAID array and need guaranteed CMR compatibility
  • ✓ Your server runs 24/7 under heavy sustained load
Buy MDD →
Choose WD Ultrastar 20TB SATA if:
  • ✓ You're comfortable with datacenter refurb to maximize savings
  • ✓ You need high-density storage for bulk/archive workloads
Buy WD →

Frequently Asked Questions

MDD 20TB offers better value at $27.00/TB vs $28.00/TB - a 4% price difference. Factor in warranty length and workload rating when the price gap is small.

Mixing drives of different models in RAID is not recommended even if capacities match. Different firmware, error handling and seek patterns can cause rebuild issues. Use identical drives within the same RAID group for reliable operation.

MDD 20TB carries a longer 5-year warranty vs unknown years for WD Ultrastar. Longer warranty typically correlates with manufacturer confidence in reliability.

MDD 20TB is the better fit for NAS storage. It uses CMR recording which is safe for all RAID levels. SATA interface is compatible with all NAS platforms including Synology, QNAP and TrueNAS.