DatacenterDisk

HP 695510-B21 vs Seagate Constellation

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

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Our Recommendation
👑
Seagate Constellation ES 4TB SAS 6G

Seagate Constellation ES 4TB SAS 6G balances price ($29.75/TB), warranty (— years), and 550TB/yr workload rating for the best overall value.

Best $/TB: HP
Best Warranty: Seagate
Best for RAID: Seagate
Full Specification Comparison
Spec
HP
695510-B21 4TB SAS 6G
$13.75/TB
Seagate
Constellation ES 4TB SAS 6G
$29.75/TB
Brand
HP
Seagate
Model
695510-B21 4TB SAS 6G
Constellation ES 4TB SAS 6G
Series
ProLiant OEM
Constellation
Part Number
695510-B21
ST4000NM0023
$/TB
👑$13.75
$29.75
Price
$55.00
$119.00
Condition
New
Refurb
Capacity
4TB
4TB
Interface
SAS-6G
SAS-6G
Form Factor
3.5"
3.5"
Drive Type
HDD
HDD
Recording Tech
CMR
CMR
RPM
7,200
7,200
Cache
—
128MB
Sector Size
512n
512e
Workload Rating
—
550TB/yr
DWPD
N/A
N/A
Warranty
—
—
Workload Tier
nearline
nearline
In Stock
Check
Check
Buy
Buy on Amazon →
Buy on Amazon →
Workload Fit
Workload
HP
Seagate
NAS Storage
●●
●●
Backup Target
●●●
●●●
OLTP Database
●
●
Cold Archive
●
●
Virtualization
●
●
AI/ML Storage
●
●
Buying Recommendation
Choose HP 695510-B21 4TB SAS 6G if:
  • ✓ You need maximum storage per dollar
  • ✓ You need new-with-warranty for compliance or budgeting
Buy HP →
Choose Seagate Constellation ES 4TB SAS 6G if:
  • ✓ You're building a RAID array and need guaranteed CMR compatibility
  • ✓ Your server runs 24/7 under heavy sustained load
  • ✓ You're comfortable with datacenter refurb to maximize savings
Buy Seagate →

Frequently Asked Questions

HP 695510-B21 offers better value at $13.75/TB vs $29.75/TB - a 54% 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.

Both drives carry similar warranty terms and are built for enterprise operation. Check brand-specific AFR data and Backblaze drive stats for real-world failure rate comparisons.

HP 695510-B21 is the better fit for NAS storage. It uses CMR recording which is safe for all RAID levels. SAS interface requires a SAS HBA or SAS-capable NAS.