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WD Black SN850X 4TB · bare — PCIe 4.0 · 7300/6600 MB/s · 4TB
Western Digital

WD Black SN850X 4TB · bare

PCIe 4.0 · 7300/6600 MB/s · 4TB

86
/ 100
From $360
VS
WD Blue SN580 2TB — PCIe 4.0 · 4150/4150 MB/s · 2TB
Western Digital

WD Blue SN580 2TB

PCIe 4.0 · 4150/4150 MB/s · 2TB

86
/ 100
From $180
Specdex verdict

Dead heat — it comes down to priorities.

In our weighted Specdex score, WD Black SN850X 4TB · bare lands at 86 and WD Blue SN580 2TB at 86. With scores tied, the decision hinges on which sub-scores matter most to you.

Pick WD Black SN850X 4TB · bare if…

  • ✓M.2 NVMe
  • ✓Competitive per-GB cost
  • ✓TBW scales with capacity

Pick WD Blue SN580 2TB if…

  • ✓M.2 NVMe
  • ✓Competitive per-GB cost
  • ✓TBW scales with capacity
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Winner by scenario

Derived from the sub-score breakdown · not a separate test

Endurance & reliability

Tie

Write endurance and long-term dependability

Effectively tied — neither pulls a 2-point weighted lead.

Value for money

WD Blue SN580 2TB

Specdex score per dollar at MSRP

WD Blue SN580 2TB more score per dollar ($180 vs $360).

WD Black SN850X 4TB · bare 86
vs
86 WD Blue SN580 2TB

Score breakdown

WD Black SN850X 4TB · bare
86
read 90
write 88
endurance 88
value 84
WD Blue SN580 2TB
86
read 90
write 88
endurance 88
value 84

Specs side-by-side

WD Black SN850X 4TB · bare versus WD Blue SN580 2TB — full spec comparison
Spec WD Black SN850X 4TB · bare WD Blue SN580 2TB
Interface
PCIe 4.0
PCIe 4.0
Capacity
▲ 4TB
2TB
Read/Write
7300/6600 MB/s
4150/4150 MB/s

WD Black SN850X 4TB · bare

Pros
  • +M.2 NVMe
  • +Competitive per-GB cost
  • +TBW scales with capacity
Cons
  • −Thermals on Gen 5 drives
  • −DRAM-less models slower under sustained load
  • −Require heatsinks in many systems

WD Blue SN580 2TB

Pros
  • +M.2 NVMe
  • +Competitive per-GB cost
  • +TBW scales with capacity
Cons
  • −Thermals on Gen 5 drives
  • −DRAM-less models slower under sustained load
  • −Require heatsinks in many systems

FAQ: WD Black SN850X 4TB · bare vs WD Blue SN580 2TB

Which is better, WD Black SN850X 4TB · bare or WD Blue SN580 2TB? +

Both score 86 on our weighted rubric — tied. Your best pick depends on the sub-scores above.

Is WD Black SN850X 4TB · bare worth the price? +

At $360, WD Black SN850X 4TB · bare delivers a Specdex score of 86 — strongest in read.

Is WD Blue SN580 2TB worth the price? +

At $180, WD Blue SN580 2TB delivers a Specdex score of 86 — strongest in read.

Does WD Black SN850X 4TB · bare or WD Blue SN580 2TB last longer? +

Based on our long-term update and support ratings, both ship with multi-year support. Battery and reliability scores are visible in the breakdown above.

Which is the better value, WD Black SN850X 4TB · bare or WD Blue SN580 2TB? +

WD Blue SN580 2TB — more score per dollar ($180 vs $360). Specdex score per dollar at MSRP.