QNAP · Business models
QNAP TS-h665U
The QNAP TS-h665U is a 4-bay rackmount NAS built around the Intel 4-core processor processor. Installed memory is 8 GB DDR5 SODIMM, expandable to 16 GB. Networking is 2 x 2.5GbE. It also has 2 x E1.S / M.2 NVMe Gen 3 x1 for SSD cache or fast storage.
- Drive bays
- 4
- Processor
- Intel 4-core processor
- Memory
- 8 GB DDR5 SODIMM
- Network
- 2.5GbE
Who it suits
A rackmount unit suits an office with a server rack or a comms room. It works well as the main file server or as a backup target for servers and PCs.
QNAP TS-h665U specifications
| Processor | Intel 4-core processor |
|---|---|
| Memory installed | 8 GB DDR5 SODIMM |
| Maximum memory | 16 GB (1 x 16 GB) |
| Drive bays | 4 x 3.5" SATA |
| M.2 slots | 2 x E1.S / M.2 NVMe Gen 3 x1 |
| Network ports | 2 x 2.5GbE |
| USB ports | 3 x USB 2.0, 1 x USB 3.2 Gen 2 Type-A |
| Expansion slots | 1 x PCIe Gen 3 x2 |
| HDMI | none |
| Form factor | Rackmount 1U |
| Size (H × W × D) | 43.3 x 430 x 374.9 mm |
| Power supply | 250 W |
| Warranty | 3 years |
| Versions sold | TS-h665U-8G (8 GB) |
Specifications from QNAP's published data, checked October 2026. See the TS-h665U on QNAP's website. Confirm details before ordering.
Usable capacity by RAID level
How much space the TS-h665U gives with typical drive sizes.
| RAID level | 4 × 4 TB | 4 × 8 TB | 4 × 12 TB | 4 × 16 TB | 4 × 20 TB |
|---|---|---|---|---|---|
| RAID 5 | 12 TB | 24 TB | 36 TB | 48 TB | 60 TB |
| RAID 6 | 8 TB | 16 TB | 24 TB | 32 TB | 40 TB |
| RAID 10 | 8 TB | 16 TB | 24 TB | 32 TB | 40 TB |
Space is shown before formatting; expect about 10% less in use. Larger systems are often split into more than one RAID group.
What we do with it
- Storage
NAS supply and installation
A right-sized Synology, QNAP or Asustor unit with the drives, RAID level and network setup your office needs.
- Backup
Automatic backup setup
Scheduled backups of PCs, servers and shared folders to the NAS, with an off-site copy, so nobody has to remember to do it.
- Versions
Ransomware protection for NAS
Point-in-time snapshots and protected copies that let you roll a folder back to how it was before an attack or a mistake.
- Move
Data migration
We move your files, users and permissions from old servers, external drives or an ageing NAS.
Questions about the TS-h665U
How much usable storage does the TS-h665U give?
It depends on the drives and the RAID level. With 4 × 8 TB drives in RAID 5 you get about 24 TB before formatting. The capacity table on this page shows other combinations.
Can the memory in the TS-h665U be upgraded?
Yes. It ships with 8 GB DDR5 SODIMM and QNAP lists a maximum of 16 GB.
Does the TS-h665U have 10GbE?
Not built in. Its ports are 2 x 2.5GbE. It has an expansion slot, which can take a faster network card where QNAP lists one for this model.
What warranty does the TS-h665U have?
QNAP lists a hardware warranty of 3 years for this model.
Do you supply the TS-h665U with drives and installation?
Yes. We supply it with compatible drives fitted, configured and tested, and can install it at your office. Ask for a quote on this page.
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