UNAS Pro 4 vs Pro 8 vs UNAS 4: Which UniFi NAS Should You Buy?

The UNAS 4, UNAS Pro 4, and UNAS Pro 8 all run the same UniFi Drive software, but they are designed for different physical environments — a desktop, a 1U rack slot, and a 2U server chassis. This guide maps each model to the use cases it is best suited for.

This article covers the three models buyers most commonly compare. For the complete lineup including the UNAS 2 ($199) and original UNAS Pro ($499), see our UniFi NAS Buyer's Guide.

Availability note (March 2026): The UNAS Pro 4 ($499) and UNAS Pro 8 ($799) are in stock at the Ubiquiti Store. The UNAS 4 ($379) launched in Q1 2026 but is currently sold out — subscribe to restock notifications on the Ubiquiti Store.

UNAS 4 vs Pro 4 vs Pro 8: At a Glance

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Core Differences Between the UNAS 4, Pro 4, and Pro 8

The UNAS 4 is a desktop unit for home and small office use, the Pro 4 is a 1U rackmount for small businesses, and the Pro 8 is a 2U enterprise unit for scaling storage and redundancy.

UNAS 4: Desktop Form Factor, PoE Power

The UNAS 4 is a compact desktop unit powered by PoE+++ — a single Ethernet cable from a compatible switch or the included 90W adapter handles both data and power. No rack required, no separate power run needed. At 246 × 129 × 224.5 mm and 5.7 lb, it sits on a desk, shelf, or next to a patch panel in a closet.

The trade-off is processing power and network speed. The ARM Cortex-A55 at 1.7 GHz with 4 GB RAM handles backup, file sharing for a small number of users, and camera footage archival well. Under concurrent multi-user access, throughput is limited by both the processor and the 2.5GbE link.

UNAS Pro 4: 1U Rackmount with Dual 10G SFP+

The UNAS Pro 4 is a 1U rackmount NAS with dual 10G SFP+ ports, NVMe read caching, and four hot-swap drive bays for $499.

It is the most compact UniFi NAS delivering 10G throughput. Cached sequential reads reach 700–900 MB/s in production environments with NVMe drives installed. It operates without per-seat licensing, making it a cost-effective appliance for offices already utilizing 10G-capable UniFi switches. The USP-RPS DC input provides power failover without fully redundant internal power supplies.

UNAS Pro 8: 2U Rackmount with 8 Bays and Redundant Power

The UNAS Pro 8 is an 8-bay, 2U rackmount NAS with dual redundant hot-swap PSUs, 16 GB RAM, and triple 10G networking for $799.

It doubles the bay count over the Pro 4 (8 vs 4), doubles the RAM (16 GB vs 8 GB), and adds a native 10GbE RJ45 port alongside two SFP+ ports. The 2U chassis at 480mm depth requires a full-depth rack and weighs 25.35 lb. It is the only UNAS that supports multiple RAID groups and hot spare drives, enabling separate RAID arrays for different workloads with automatic rebuild on standby.

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Storage Capacity and RAID Limitations

The 4-bay UNAS 4 and Pro 4 support a single RAID group, while the 8-bay UNAS Pro 8 supports multiple RAID groups and hot spare drives.

Drive bay count dictates both total capacity and fault tolerance:

With four bays in RAID 5, a single drive failure is tolerable — you get ~54 TB usable with 18 TB drives. With eight bays, the Pro 8 can run RAID 6 (two-drive fault tolerance) and still deliver ~108 TB of usable space with 18 TB drives — or split the array into multiple RAID groups with a hot spare for automatic rebuild.

NVMe Cache Differences

All three models include two M.2 NVMe slots for SSD caching, but the cap differs:

• UNAS 4: Max 2 TiB per NVMe slot
• UNAS Pro 4 and Pro 8: Max 4 TiB per NVMe slot

NVMe caching accelerates read-heavy workloads — frequently accessed files are served from SSD rather than spinning disk. The 2 TiB limit on the UNAS 4 is adequate for most home and small office use, but businesses with larger active datasets benefit from the 4 TiB ceiling on the Pro models.

Recommended Drives for UniFi NAS

For NVMe cache slots: any PCIe 3.0/4.0 M.2 2280 NVMe SSD works. High-endurance options (WD Red SN700, Samsung PM9A3) are preferred for sustained cache writes. Maximum per slot: 2 TiB (UNAS 4) or 4 TiB (Pro 4 and Pro 8).

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Network Speed Comparison: 2.5GbE vs 10G SFP+ vs 10GbE RJ45

The UNAS 4 is limited to 2.5GbE (~280 MB/s), while both Pro models deliver 10G networking via SFP+ ports. Only the Pro 8 includes a native 10GbE RJ45 copper port.

UNAS 4 tops out at approximately 280 MB/s, which is adequate for document sharing and backup for a small number of users. It is not suited for video editing workflows or large concurrent file transfers.

UNAS Pro 4 delivers dual 10G SFP+ with cached reads reaching 700–900 MB/s. It requires an SFP+-capable switch (UniFi Pro Max 24/48 PoE, Pro XG 24, or similar). If your switch only has RJ45 ports, you will need SFP+ to RJ45 transceivers at $30–$65 each. Note that 10GBASE-T SFP+ transceivers run significantly hotter than DAC cables (surface temperatures of 70–90°C are common) and draw 3–8W each — factor this into rack thermal planning for a 1U chassis.

UNAS Pro 8 includes the same dual 10G SFP+ ports plus a native 10GbE RJ45 port that auto-negotiates down to 5G/2.5G/1G. It works in both SFP+ fiber and copper environments without additional transceivers.

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Processor and RAM Specifications

The UNAS 4 uses an ARM Cortex-A55 with 4 GB RAM. Both Pro models use a faster ARM Cortex-A57, with the Pro 4 at 8 GB and the Pro 8 at 16 GB. None are user-upgradable.

RAM is soldered on all three models.

The UNAS 4's A55 at 1.7 GHz is a lower-power core suited for file serving and NFS/SMB access for a small number of users. Performance degrades under concurrent multi-protocol access from larger groups.

The Pro models share the same A57 at 2.0 GHz, but the Pro 8's 16 GB RAM provides meaningful headroom. With 8 bays worth of data and multiple users accessing different shares simultaneously, the extra memory reduces cache thrashing and improves response times. For an office of 20+ employees hitting the NAS regularly, 16 GB is the right baseline.

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Power Supply and Redundancy

The UNAS 4 runs on PoE+++, the Pro 4 uses a single AC supply with RPS failover, and only the Pro 8 has true dual redundant hot-swap power supplies.

The UNAS 4's PoE+++ power allows placement near a PoE switch without a separate power outlet. A PoE switch backed by a UPS also provides power protection for the NAS.

The UNAS Pro 4 accepts AC power plus a secondary DC input from the UniFi SmartPower Redundant Power System. This is not true redundancy (the RPS kicks in only on AC failure), but it is a meaningful step above a single power source.

The UNAS Pro 8 is the only model with true dual redundant hot-swappable power supplies. If one PSU fails, the other takes over with zero downtime. For businesses with uptime SLAs or compliance requirements, this ensures continuity without a secondary failover device.

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Fan Noise and Placement Considerations

The UNAS 4 is the quietest model in the lineup, suitable for placement near workstations. Both rackmount Pro models use server-grade fans that are audible under load.

The UNAS 4's desktop enclosure with larger, slower-spinning fans runs quietly enough for a home office or closet placement. The UNAS Pro 4's 1U chassis uses small, high-RPM fans — standard for 1U server hardware — that are noticeably louder than the desktop model or the Pro 8's larger 2U fans. Do not place a Pro 4 in an open office next to workstations. The UNAS Pro 8's 2U chassis allows larger fan blades at lower RPM, producing less noise per cubic foot of airflow than the Pro 4, though it is still server-room hardware.

For all three models, noise increases under drive rebuild or heavy sequential write loads. Plan for enclosed rack, closet, or server room placement for the Pro models.

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Best UNAS for Home Use and UniFi Protect Archival

The scenario: You run UniFi Protect cameras at home or a small site and want long-term footage archival beyond what the NVR retains. You also want a central file server for household backups, media, and Time Machine.

Why the UNAS 4 fits:

• PoE+++ power allows placement near your network closet using a single Ethernet cable, with no separate power outlet required
• 4 bays in RAID 5 provides ~24–54 TB usable capacity (depending on drive size — 8 TB to 18 TB), sufficient for long-term footage archival and personal file storage
• 2.5GbE is more than enough for Protect archive transfers and home file sharing
• 1.47" color LCD shows status without needing the UniFi console
• $379 keeps total investment low when paired with NAS-grade drives

Important limitation: The UNAS does not run UniFi Protect. It archives footage from a separate Protect device (UNVR, UDM Pro, UDM Pro Max) via the export/archival feature. You still need a dedicated Protect NVR for live recording and camera management.

Typical home deployment cost:

• UNAS 4: $379
• 4× Seagate IronWolf 8TB: ~$640
• Total: ~$1,019 (no switch upgrade needed if already on GbE/2.5GbE)

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Best UNAS for Small Business (5–25 Employees)

The scenario: Your office has 5–25 employees sharing documents, project files, and backups. You run a UniFi rack with a gateway, PoE switch, and possibly Protect cameras. You need fast, reliable file storage that manages from the same console.

Why the Pro 4 fits:

• Dual 10G SFP+ connects directly to your UniFi Pro Max switch uplinks — no transceivers needed if your switch has SFP+ slots
• NVMe caching accelerates access to frequently used files, with cached reads reaching 700–900 MB/s
• 1U form factor preserves rack space — pair it with a UDM Pro Max, a Pro Max 24 PoE switch, and a UPS in a compact 12U rack
• 8 GB RAM handles 10–20 concurrent SMB/NFS connections without issue
• License-free — no per-seat charges, no subscriptions, no renewal anxiety
• UNAS-to-UNAS replication enables automated backup to a second UNAS at another site

Key constraints to plan for:

• 4 bays means ~54 TB usable in RAID 5 with 18 TB drives — adequate for most SMBs, but no room to grow beyond that
• Single RAID group only — all four drives must be in one array
• No Docker, VMs, or iSCSI — this is a file and backup appliance, not a general-purpose server

Note on the original UNAS Pro: Ubiquiti's store also lists the older 7-bay UNAS Pro at $499. It has more bays but lacks NVMe caching, has only a single 10G SFP+ port, and uses an older 2U chassis. For most new buyers, the Pro 4 is the better $499 option; the 7-bay Pro is worth considering only if you specifically need more than 4 bays and cannot stretch to the Pro 8.

Typical SMB deployment cost:

• UNAS Pro 4: $499
• 4× WD Red Pro 18TB: ~$1,200
• 2× NVMe 1TB cache: ~$120
• SFP+ DAC cables (2×): ~$30
• Total: ~$1,849 (assuming existing 10G switch)

We deploy the Pro 4 in client offices across South Florida where the requirement is fast file sharing managed from a single console with no per-seat licensing. It handles that role well.

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Best UNAS for Growing Businesses and Multi-Site Deployments

The scenario: Your business has more than 20 employees, you handle regulated data, or you operate multiple sites that need replicated storage.

Why the Pro 8 fits:

• 8 bays mean you start with 4 drives and expand to 8 over time — or run RAID 6 (two-drive fault tolerance) with 6+ drives from day one
• Multiple RAID groups let you separate file shares from Protect archival or backup volumes on the same appliance
• Hot spare support keeps a standby drive ready for automatic rebuild without manual intervention
• Dual redundant hot-swap PSUs mean a power supply failure does not take storage offline
• 16 GB RAM handles 30–50+ concurrent connections and larger active file sets without cache pressure
• Native 10GbE RJ45 connects directly to copper switches — no SFP+ modules needed if your infrastructure is RJ45-based
• UNAS-to-UNAS replication across sites gives you 3-2-1 backup compliance without third-party software

Typical growing-business deployment cost:

• UNAS Pro 8: $799
• 6× Seagate IronWolf Pro 18TB: ~$2,100
• 2× NVMe 2TB cache: ~$200
• 1× hot spare 18TB drive: ~$350
• Total: ~$3,449 (drives are always the biggest cost)

For businesses in regulated industries — healthcare, legal, financial services — the Pro 8's redundant power and multi-RAID support address common audit requirements around storage availability. Paired with cloud backup to Backblaze B2 or Wasabi, it supports a 3-2-1 backup configuration.

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Best UNAS for Video Editing and Content Creation

The scenario: You edit 4K/6K video, manage large photo libraries, or run a design studio where team members pull multi-gigabyte files from shared storage regularly.

Network speed matters here: A 30 GB video project file takes approximately 2 minutes to transfer over 2.5GbE. Over 10G SFP+ with NVMe caching, that drops to under 30 seconds. For teams doing this repeatedly throughout a workday, the difference is meaningful.

UNAS Pro 4 for solo/small studio:

• 4 bays in RAID 5 with 18 TB drives = 72 TB raw, ~54 TB usable
• NVMe caching keeps actively-edited project files on SSD-speed storage
• Dual SFP+ links allow simultaneous ingest and edit access without congestion
• $499 total NAS cost keeps the budget for drives and a good monitor

UNAS Pro 8 for multi-editor studio:

• 8 bays in RAID 6 with 22 TB drives = ~176 TB raw, ~132 TB usable with two-drive redundancy
• 16 GB RAM handles multiple editors pulling different project files simultaneously
• Multiple RAID groups let you keep a fast "working" pool (4 drives, RAID 10) and a deep "archive" pool (4 drives, RAID 5) on the same box
• Native 10GbE RJ45 means one less transceiver to troubleshoot

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Total Cost of Ownership: UNAS 4 vs Pro 4 vs Pro 8

The NAS unit price is only part of the total investment. Drives, 10G switch requirements, and power protection shift the real cost gap between models:

The $420 gap between the UNAS 4 and Pro 4 narrows when you already own a 10G switch. Conversely, if you need to buy a switch to use the Pro 4's SFP+ ports, the effective gap can reach $800+ — which makes the Pro 8 with its 10GbE RJ45 port a more compelling upgrade.

All three models are license-free with no per-seat charges. A comparable Synology DS925+ ($600) plus a Synology camera license pack quickly exceeds the UNAS Pro 4 in total spend, and the Synology RS422+ rackmount ($750+) has no 10G and only 4 bays.

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Firmware Maturity: What Early Adopters Should Know

The UNAS Pro 4 and Pro 8 run mature UniFi Drive firmware (4.x). The UNAS 4 is a newer release and may encounter early-adopter firmware issues typical of new Ubiquiti hardware.

The Pro models have benefited from months of production use across the original UNAS Pro and Pro 8 hardware, with Drive 4.0 (February 2026) adding M365 OneDrive backup and S.M.A.R.T. monitoring. The UNAS 4's ARM Cortex-A55 architecture is newer to the UniFi Drive platform, and early r/Ubiquiti threads report occasional firmware-related stability issues under sustained load — consistent with the pattern Ubiquiti follows on most new hardware launches. These are typically resolved within 2–3 firmware cycles.

If you are buying the UNAS 4 for a business-critical role, monitor the Ubiquiti Community forums for firmware release notes before deploying in production. For the Pro 4 and Pro 8, the firmware is stable and well-tested in our client deployments.

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Migrating to a New UNAS from an Existing Device

There is no one-click migration between UNAS models. Data transfer requires either UNAS-to-UNAS replication or a manual network file copy.

If you are replacing an older UNAS Pro (7-bay) with a Pro 4 or Pro 8, the recommended approach is to configure the new device as a replication target, sync your data, then promote it to primary. For users moving from a Synology or other third-party NAS, plan for a direct SMB/NFS file transfer over the network — there is no import tool in UniFi Drive that reads foreign RAID arrays or backup formats. With 10G networking, a full 40 TB transfer completes in approximately 10–12 hours.

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UniFi Drive Software: Features and Limitations

All three models run the same UniFi Drive OS with identical software capabilities. UniFi Drive is Ubiquiti's license-free NAS operating system, managed through the UniFi console.

Shared capabilities across all three models:

• File protocols: NFS and SMB (no iSCSI, no AFP)
• Cloud backup: Google Drive, OneDrive, Dropbox, Amazon S3, Backblaze B2, Wasabi
• Microsoft 365 OneDrive backup (added in Drive 4.0, February 2026)
• S.M.A.R.T. drive health monitoring in the UniFi console
• UNAS-to-UNAS replication for offsite backup between UniFi NAS devices
• Snapshots for point-in-time recovery
• File encryption at rest
• Time Machine backup for Mac workstations
• Share links for external file sharing
• UniFi Identity integration for user management
• Personal and shared drives per user/group
• Third-party backup ingress via SMB: A Synology or QNAP can push backups to a UNAS share using Synology Hyper Backup or QNAP Hybrid Backup Sync with SMB as the destination. UniFi Drive does not run a native rsync daemon, but standard SMB-based backup jobs from third-party NAS devices work reliably.

What UniFi Drive does not support (on any model):

• Docker containers or virtual machines
• iSCSI block storage
• Native UniFi Protect recording (archival only, from a separate NVR)
• Active Directory domain joining (UniFi Identity only)
• Third-party app packages (unlike Synology DSM or QNAP QTS)
• Plex, Jellyfin, or other media server applications

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When to Choose Synology or TrueNAS Instead

UniFi NAS is strictly a file serving and backup appliance. Users who need Docker containers, virtual machines, Plex media servers, or iSCSI block storage must choose a different platform.

Ubiquiti has scoped the UNAS lineup to SMB/NFS file serving, cloud backup, and UniFi ecosystem integration. There is no app store, no container runtime, and no support for third-party software on any UNAS model. If your requirements include any of the following, a different platform is more appropriate:

• Media server (Plex, Jellyfin, Emby): Choose a Synology DS925+ or UGREEN DXP4800 Plus, both of which run Docker natively. See our best NAS for small business comparison for a side-by-side analysis.
• Virtual machines or development environments: Synology Virtual Machine Manager or a dedicated TrueNAS server.
• iSCSI block storage for VMware/Hyper-V: Synology or QNAP with iSCSI target support.
• Active Directory domain controller: Windows Server or Synology Directory Server. UniFi NAS uses UniFi Identity only.
• Extensive third-party integrations: Synology DSM's package ecosystem remains significantly broader than UniFi Drive.

UniFi NAS offers zero-licensing simplicity and unified management within the UniFi ecosystem. It is not a general-purpose server, and Ubiquiti has not indicated plans to change that scope.

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Which UniFi NAS Should You Buy?

Choose the UNAS 4 ($379) if you need desktop NAS storage without rack infrastructure. It is the right pick for home labs, UniFi Protect footage archival, personal backup, and small offices with fewer than 5 users. PoE+++ power and the compact form factor make deployment effortless.

Choose the UNAS Pro 4 ($499) if you run a UniFi rack and need fast, license-free file storage for 5–25 employees. The dual 10G SFP+ and NVMe caching deliver genuine 10G performance, and the 1U form factor keeps your rack tidy. This is the model we deploy most often in client offices.

Choose the UNAS Pro 8 ($799) if your business is growing, you require redundant power, or you need more than 4 drive bays. The $300 premium over the Pro 4 adds double the bays, double the RAM, dual redundant PSUs, multiple RAID groups, hot spare support, and a native 10GbE RJ45 port — features that matter in environments where storage uptime is a business requirement.

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Related Resources

• UniFi NAS Buyer's Guide 2026 — Full lineup comparison including UNAS 2 and original UNAS Pro with pricing and spec details.
• UNAS Pro 4 Review — In-depth review of the 1U rackmount NAS with real SMB deployment data and Active Directory integration testing.
• Best NAS for Small Business 2026 — Cross-brand comparison including Synology DS925+ and UGREEN DXP4800 Plus for buyers considering alternatives.
• UniFi Drive 4.0 vs Synology — Software platform analysis comparing UniFi Drive features and limitations against Synology DSM.
• Best UPS for UniFi Rack — Power protection recommendations for UNAS Pro rack deployments including graceful shutdown configuration.
• Complete UniFi Buyer's Guide — Gateway, switch, and access point recommendations for the broader UniFi ecosystem.