Verdict

These are comparable SSDs. The SNV3410-800G is rated for the most write endurance, so it lasts longest in a NAS that sees steady writes; for light use any is fine and price decides.

SNV3410-800G
Synology SNV3410 · 0.8TB · NAS
No IT price yet
SNV3510-400G
Synology SNV3510 · 0.4TB · NAS
No IT price yet

Value at a glance

Endurance (TBW)
SNV3410-800G 1,022 TB
SNV3510-400G 491 TB
DWPD
SNV3410-800G 0.7
SNV3510-400G 0.7
SNV3410-800G SNV3510-400G
Capacity 0.8 TB 0.4 TB
Form factor M.2 M.2
Interface NVMe NVMe
NAND type TLC TLC
Endurance (TBW) 1,022 TB 491 TB
DWPD 0.7 0.7
DRAM cache - -
Power-loss protection No Yes
Sustained write - -
Cost / TBW - -
Price / TB - -
Buy No IT price yet No IT price yet

Highlighted cells mark the stronger spec for a NAS build. Failure rates from Backblaze Drive Stats where available; $/TB uses the cheapest live price. Buy links are Amazon affiliate.

SNV3410-800G

No Backblaze failure data for this model.

SNV3510-400G

No Backblaze failure data for this model.