Western Digital Red 4TB
NAS HDD
Part number WD40EFRX - 68N32N0 · Red series · 3.5" SATA HDD. If your machine is listed below, this drive is officially supported — not a forum workaround.
Part of the Western Digital Red series →
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Specifications are the manufacturer's published ratings for this product series; verify the exact part number before purchase.
Recording for this series is mixed CMR/SMR — it varies by exact model number. Verify the exact part number before buying a cold copy: SMR drives throttle writes once their internal cache is full, which is exactly what a full-library backup pass does — a 16 TB cold-copy backup that takes days will slow to crawl on the last terabytes. For the off-site slot of a 3-2-1 plan, prefer the CMR variant of the same capacity; the 3-2-1 guide and the backup tools encyclopedia cover the rest of the chain.
Compatibility verdict
It appears on the official compatibility lists of 133 machines and series — 133 Synology. This is a NAS-class drive: built for 24/7 operation with vibration compensation for multi-bay enclosures — the right tier for most 1-8 bay home or small-office NAS units. Its series rating is on file as SMR (shingled) — the one trait that slows large RAID rebuilds and full-library copies.
Compatible NAS models
Same-capacity alternatives
Other drives listed at 4 TB capacity, ranked by how many machines list them:
Quick answers
Is the WD40EFRX - 68N32N0 officially compatible with my NAS?
It appears on the official compatibility lists of 133 machines and series — 133 Synology. Every machine page linked below shows the vendor's own list entry, refreshed daily.
Is the WD40EFRX - 68N32N0 CMR or SMR?
As a Western Digital Red drive, it is rated CMR/SMR varies by model. CMR (conventional magnetic recording) is what a RAID array wants: SMR drives slow rebuilds dramatically. This series mixes both, so verify the exact part number before buying — the <a href="/faq/cmr-vs-smr-nas-drives/">CMR vs SMR guide</a> has a part-number lookup.
Is the WD40EFRX - 68N32N0 a good NAS drive?
This is a NAS-class drive: built for 24/7 operation with vibration compensation for multi-bay enclosures — the right tier for most 1-8 bay home or small-office NAS units. Its series rating is on file as SMR (shingled) — the one trait that slows large RAID rebuilds and full-library copies.
Can I use the WD40EFRX - 68N32N0 for a 3-2-1 cold backup copy?
Recording for this series is mixed CMR/SMR — it varies by exact model number. Verify the exact part number before buying a cold copy: SMR drives throttle writes once their internal cache is full, which is exactly what a full-library backup pass does — a 16 TB cold-copy backup that takes days will slow to crawl on the last terabytes. For the off-site slot of a 3-2-1 plan, prefer the CMR variant of the same capacity; the 3-2-1 guide and the backup tools encyclopedia cover the rest of the chain.
What are alternatives to the WD40EFRX - 68N32N0?
At the same capacity, the most widely listed alternatives are Toshiba MG04ACA400E (451 machines), Western Digital WD4003FFBX (390 machines), Seagate ST4000NE0015 (379 machines). The full ranked list is below.