QNAP · Business models
QNAP TS-855X
The QNAP TS-855X is a 8-bay desktop NAS built around the Intel Atom C5125 processor. Installed memory is 8 GB DDR4 UDIMM, expandable to 128 GB. Networking is 2 x 2.5GbE, 1 x 10GBASE-T. It also has 2 x M.2 2280 PCIe Gen 3 x4 for SSD cache or fast storage.
- Drive bays
- 8
- Processor
- Intel Atom C5125
- Memory
- 8 GB DDR4 UDIMM
- Network
- 10GbE
Who it suits
Eight bays allow RAID 6 with plenty of usable space, or separate fast and bulk storage pools. A common choice for 25 to 100 users.
QNAP TS-855X specifications
| Processor | Intel Atom C5125, 8-core, 2.8 GHz |
|---|---|
| Memory installed | 8 GB DDR4 UDIMM (non-ECC) |
| Maximum memory | 128 GB (4 x 32 GB) |
| Drive bays | 6 x 3.5" SATA + 2 x 2.5" SATA |
| M.2 slots | 2 x M.2 2280 PCIe Gen 3 x4 |
| Network ports | 2 x 2.5GbE, 1 x 10GBASE-T |
| USB ports | 1 x USB 2.0, 3 x USB 3.2 Gen 1 |
| Expansion slots | 2 x PCIe Gen 3 x4 |
| HDMI | none |
| Form factor | Desktop |
| Size (H × W × D) | 225 x 292.9 x 319.8 mm |
| Weight | 10.04 kg |
| Power consumption | 86.96 W operation |
| Power supply | 250 W |
| Warranty | 3 years |
| Versions sold | TS-855X-8G (8 GB) |
Specifications from QNAP's published data, checked October 2026. See the TS-855X on QNAP's website. Confirm details before ordering.
Usable capacity by RAID level
How much space the TS-855X gives with typical drive sizes.
| RAID level | 6 × 4 TB | 6 × 8 TB | 6 × 12 TB | 6 × 16 TB | 6 × 20 TB |
|---|---|---|---|---|---|
| RAID 5 | 20 TB | 40 TB | 60 TB | 80 TB | 100 TB |
| RAID 6 | 16 TB | 32 TB | 48 TB | 64 TB | 80 TB |
| RAID 10 | 12 TB | 24 TB | 36 TB | 48 TB | 60 TB |
These figures count only the 3.5-inch bays. 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-855X
How much usable storage does the TS-855X give?
It depends on the drives and the RAID level. With 6 × 8 TB drives in RAID 5 you get about 40 TB before formatting. The capacity table on this page shows other combinations.
Can the memory in the TS-855X be upgraded?
Yes. It ships with 8 GB DDR4 UDIMM and QNAP lists a maximum of 128 GB.
Does the TS-855X have 10GbE?
Yes. Its network ports are 2 x 2.5GbE, 1 x 10GBASE-T.
What warranty does the TS-855X have?
QNAP lists a hardware warranty of 3 years for this model.
Do you supply the TS-855X 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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