Pick an NVMe Drive That Lasts as a NAS Cache
10 NVMe model numbers with a datasheet endurance figure
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A cache drive is written far more than a storage drive, so the figure to buy on is rated endurance. Of the NVMe model numbers with a maker's figure recorded here, the highest is the 4TB WD Red SN700 WDS400T1R0C at 5,100 TBW. Capacity for capacity, the WD Red SN700 is rated at 2.0 TB per GB at 250GB and 1.3 TB per GB at 4TB, and Synology's SNV5420 at 1.8 TB per GB or more. On a Synology 2025 model the question is settled for you: only Synology's own drives can create a cache.
Rated endurance, by model number
| Line | Model | Capacity | Rated endurance | Per gigabyte of capacity | Limited warranty |
|---|---|---|---|---|---|
| WD Red SN700 | WDS400T1R0C | 4TB | 5,100 TBW | 1.3 TB per GB | 5 years or the TBW limit |
| Synology SNV5420 | SNV5420-1600G | 1600GB | more than 2,900 TBW | 1.8 TB per GB | Not in the sheet read |
| WD Red SN700 | WDS200T1R0C | 2TB | 2,500 TBW | 1.3 TB per GB | 5 years or the TBW limit |
| WD Red SN700 | WDS100T1R0C | 1TB | 2,000 TBW | 2.0 TB per GB | 5 years or the TBW limit |
| Synology SNV5420 | SNV5420-800G | 800GB | more than 1,400 TBW | 1.8 TB per GB | Not in the sheet read |
| Synology SNV3410 | SNV3410-800G | 800GB | 1,022 TBW | 1.3 TB per GB | Not in the sheet read |
| WD Red SN700 | WDS500G1R0C | 500GB | 1,000 TBW | 2.0 TB per GB | 5 years or the TBW limit |
| Synology SNV5420 | SNV5420-400G | 400GB | more than 700 TBW | 1.8 TB per GB | Not in the sheet read |
| WD Red SN700 | WDS250G1R0C | 250GB | 500 TBW | 2.0 TB per GB | 5 years or the TBW limit |
| Synology SNV3410 | SNV3410-400G | 400GB | 491 TBW | 1.2 TB per GB | Not in the sheet read |
WD Red SN700 speeds, as WD lists them
| Capacity | Model | Sequential read | Sequential write |
|---|---|---|---|
| 250GB | WDS250G1R0C | 3,100 MB/s | 1,600 MB/s |
| 500GB | WDS500G1R0C | 3,430 MB/s | 2,600 MB/s |
| 1TB | WDS100T1R0C | 3,430 MB/s | 3,000 MB/s |
| 2TB | WDS200T1R0C | 3,400 MB/s | 2,900 MB/s |
| 4TB | WDS400T1R0C | 3,400 MB/s | 3,100 MB/s |
Reading the endurance column
TBW is the total the maker warrants the drive for. WD's warranty on the SN700 is five years or the TBW limit, whichever comes first, so a heavily written cache can use up the warranty early.
Bigger is not always proportionally tougher. The 2TB SN700 is rated at 2,500 TBW, only a quarter more than the 1TB model's 2,000 TBW, so per gigabyte the models up to 1TB carry the higher rating.
Most NAS slots are a single PCIe 3.0 lane, well under these drives' sequential speeds, so endurance and not speed is what separates them in a NAS.
Before you buy
Check what your model's slots allow and work out how long a rating lasts at your write rate.
M.2 slot specs by NAS model · NAS SSD endurance calculator · Synology-validated M.2 NVMe drives
Where the figures come from
Western Digital's WD Red product briefs and Synology's SNV product specifications, read on October 12, 2026. Each figure is the one printed beside the model number. Other makers' cache drives are not in the table because their endurance figures have not been read into this site's record.
Checked on October 12, 2026. Sources: Western Digital: WD Red SN700 NVMe SSD product brief; Synology SNV5420 product specifications (400G, 800G and 1600G sheets).
NAS NVMe drives with a datasheet endurance figure, by price
WD Red SN700 and Synology SNV drives, the lines whose endurance is in the table below.
| Product | Capacity | Price | $ / TB | Type | Prime | Buy |
|---|---|---|---|---|---|---|
| Western Digital 2TB WD Red SN700 NVMe Internal Solid State Drive SSD for NAS Devices - Gen3 PCIe, M.2 2280, Up to 3,400 MB/s - WDS200T1R0C | 2 TB | $599.95 | $299.98 | M.2 NVMe | - | Buy on Amazon |
| Western Digital 1TB WD Red SN700 NVMe Internal Solid State Drive SSD for NAS Devices - Gen3 PCIe, M.2 2280, Up to 3,430 MB/s - WDS100T1R0C | 1 TB | $499.95 | $499.95 | M.2 NVMe | - | Buy on Amazon |
| Western Digital 250GB WD Red SN700 NVMe Internal Solid State Drive SSD for NAS Devices - Gen3 PCIe, M.2 2280, Up to 3,100 MB/s - WDS250G1R0C | 250 GB | $199.00 | $796.00 | M.2 NVMe | - | Buy on Amazon |
| Synology SNV5420-400G M.2 NVMe SSD 400G | 400 GB | $587.03 | $1,467.57 | M.2 NVMe | - | Buy on Amazon |
Other M.2 2280 NVMe drives, 250GB to 4TB, by price per TB
Not NAS-branded and with no endurance figure recorded here. Check the maker's sheet for the model before using one as a write cache.
Frequently asked questions
What is the endurance of the WD Red SN700?
500 TBW at 250GB, 1,000 TBW at 500GB, 2,000 TBW at 1TB, 2,500 TBW at 2TB, 5,100 TBW at 4TB, by WD's product brief.
Which NVMe drive here has the highest rated endurance?
The 4TB WD Red SN700 WDS400T1R0C, at 5,100 TBW.
Does the WD Red SN700 warranty depend on how much is written?
Yes. WD gives five years or the TBW limit, whichever occurs first.