QNAP TS-664: Specs, Drive Compatibility and Total Build Cost

Hardware specifications, per QNAP's own spec page

Source: QNAP TS-664 hardware specifications, read 2026-09-14 — qnap.com.

QNAP's formal hardware spec table lists the M.2 slots only under "SSD Cache Acceleration Support." The TS-664's own overview/marketing page separately states "you can create a storage pool with two M.2 SSDs," used together with Qtier auto-tiering to move hot data to SSD and cold data to hard drives - not described anywhere as a fully independent, freestanding volume outside that tiering role. Both are QNAP's own text, reported as the discrepancy it is rather than resolved in either direction.

The honest total: chassis + drives, three ways

$743.07 buys the empty chassis. Filling all 6 bays is the real purchase, priced at three genuinely different tiers below.

The smallest cheque that fills all 6 bays, separately from the value tiers above: 6 x Toshiba MG03ACA200 2TB SATA Enterprise at $104.98 each = $629.88.

Drive compatibility, measured

The TS-664 carries the shortest of the three lists we captured and the only one with no HGST entries on it at all - 390 rows across WD, Seagate and Toshiba alone. It is also the machine whose list overlaps least with the others: barely a fifth of its part numbers are shared with the TS-653D. An Intel Celeron machine from a different product generation gets a genuinely different qualification set, which is the clearest evidence on this site that QNAP's per-machine lists are per-machine in substance and not just in presentation. QNAP's posture, per its own published stance, is to annotate rather than gate: an unlisted drive still builds a volume.

117 SATA HDDs in our own catalogue are fit-verified for this class of bay right now (interface, form factor and CMR-confirmed).

Full TS-664 compatible-drives page.

Expansion limits and the M.2 reality

QNAP names the TL-D1600S expansion unit, stating it adds "eighteen" hard drives - QNAP's own exact wording, though the TL-D1600S is conventionally a 16-bay unit elsewhere in QNAP's lineup; quoted as published rather than silently corrected. No vendor-stated total bay count.

The M.2 slots are the trap worth naming carefully on this specific machine, because QNAP's own pages do not agree with each other. The formal hardware spec table lists the two M.2 slots only under "SSD Cache Acceleration Support" - cache, full stop. The TS-664's own overview/marketing page separately states you can "create a storage pool with two M.2 SSDs," but frames that pool as working together with Qtier auto-tiering to move hot data to SSD and cold data to the HDD pool - not as a fully independent volume disconnected from the spinning array. We are reporting both QNAP pages rather than picking the one that reads more favourably.

The distinction matters for a buyer's money, not just their reading comprehension: a cache accelerates reads and writes to the existing spinning pool, while a tiered storage pool is genuinely separate capacity with its own place in the filesystem, managed automatically between fast and slow media. Buying two M.2 SSDs expecting one behaviour on a machine whose own documentation describes the other is exactly the kind of cost this section exists to prevent - and on the TS-664 specifically, the honest answer is that QNAP has not settled which one it means.

What else it needs

Power protection: see UPS units for a NAS, priced live with output waveform stated on every row. The TS-664's 2.5GbE ports are fixed on the built-in NIC; QNAP documents a PCIe slot for an add-in 10GbE card, sold separately - see 10GbE for a NAS for live card prices.

Sources checked: QNAP TS-664 hardware specifications, QNAP TS-664 product overview, QNAP compatibility list.