Side-by-side spec and price comparison. Live data from Amazon US.
WD Ultrastar DC SN655 7.68TB U.2 wins on both price ($38.35/TB) and warranty (5 years).
WD Ultrastar offers better value at $38.35/TB vs $38.35/TB - a 0% 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 5-year warranties and are built for enterprise operation. Check brand-specific AFR data and Backblaze drive stats for real-world failure rate comparisons.
WD Ultrastar is the better fit for NAS storage.