UGREEN NAS Thunderbolt 4: Setup and Speed Fixes

Thunderbolt direct connection is supported on the UGREEN NASync DXP480T Plus, DXP6800 Pro, and DXP8800 Plus with UGOS Pro firmware 1.2.0.2121 or later.

Thunderbolt 4 provides a 40Gbps link, but the client, SMB connection, NAS processor, storage pool, RAID configuration, file size, and background activity determine the result.

Can Your UGREEN NAS Use Thunderbolt Direct Connection?

Each listed model has two physical Thunderbolt 4 ports. Our direct-connection procedure uses one computer and one NAS port. It does not combine both ports into a faster SMB link or rely on Thunderbolt daisy-chaining.

If your current NAS is not listed and Thunderbolt connectivity is essential, use the NAS Selector to narrow the options or browse and filter NAS Storage by ports and workload.

The computer needs a Thunderbolt 3 or later port. A USB-C connector alone does not confirm Thunderbolt support because USB-C describes the connector rather than the communication protocol.

Use a certified Thunderbolt 3, Thunderbolt 4, or Thunderbolt 5 cable. Intel specifies that certified Thunderbolt 4 cables can maintain 40Gbps capability at lengths up to two meters, so the cable does not need to be shorter than 0.8 meters. See Intel’s Thunderbolt 4 specifications.

If you are unsure whether the computer or cable supports Thunderbolt, look for the Thunderbolt lightning symbol and check the computer manufacturer’s specifications.

How Does a Thunderbolt NAS Connection Work?

A UGREEN NAS remains a network storage system when connected through Thunderbolt:

Computer → Thunderbolt network connection → Dedicated IP address → SMB or UGREEN NAS client → UGOS Pro shared folder → NAS storage pool

It does not give the computer direct control of the installed drives.

UGOS Pro continues to manage the filesystem, storage pools, RAID, permissions, snapshots, and applications. The computer receives access to authorized shared folders through a high-speed network path.

This is why a UGREEN NAS connected through Thunderbolt behaves differently from a Thunderbolt DAS enclosure. Our DAS-versus-NAS guide explains the architectural difference.

How to Set Up a UGREEN NAS Thunderbolt Connection

Before connecting the cable:

• Confirm that the NAS model appears in the supported table.
• Update UGOS Pro to firmware 1.2.0.2121 or later.
• Confirm that the computer has a Thunderbolt 3, 4, or 5 port.
• Use a certified Thunderbolt cable instead of a standard USB-C charging cable.
• Create the storage pool and shared folder the computer will access.
• Keep the NAS connected to Ethernet if other devices still need LAN or remote access.

Use the UGREEN NAS Download Center if you need the firmware or desktop client for your model.

Connect the cable and find the Thunderbolt IP address

1. Connect one end of the Thunderbolt cable to the supported UGREEN NAS.
2. Connect the other end directly to the computer’s Thunderbolt port.
3. Sign in to UGOS Pro with an administrator account.
4. Open Control Panel > Network Settings > Network Connection.
5. Find the Thunderbolt network interface.
6. Record its dedicated IP address, such as 172.17.70.242.
7. Open Control Panel > File Services > SMB.
8. Enable SMB if it is not already active.

Connect from Windows

1. Open File Explorer.
2. Select This PC.
3. Open the three-dot menu and select Map network drive.
4. Choose a drive letter.
5. Enter the Thunderbolt IP address and shared-folder name:
   `\\169.254.12.125\SharedFolder`
6. Select **Reconnect at sign-in** if you want Windows to retain the mapping.
7. Enter the NAS username and password.
8. Open the mapped drive and transfer a test file.

If the UGREEN NAS client is installed, you can also select More Connections and look for the device displaying the Thunderbolt symbol.

Connect from macOS

1. Open `System Settings > Network`.
2. Confirm that **Thunderbolt Bridge** appears as a network service.
3. If it is missing, add a network service and select Thunderbolt Bridge.
4. Open Finder.
5. Select `Go > Connect to Server`.
6. Enter the Thunderbolt IP address and shared-folder name:
   `smb://169.254.12.125/SharedFolder`
7. Select Connect.
8. Enter the NAS username and password.
9. Choose the shared folder you want to mount.

Apple identifies Thunderbolt Bridge as an IP network interface, and Finder accepts SMB addresses in the `smb://IP-address/share-name` format. See Apple’s instructions for Thunderbolt Bridge and connecting to an SMB server.

You can also enable Bonjour under `Control Panel > File Services > Advanced Settings`, then look for the NAS under **Network** in Finder. Use the explicit Thunderbolt IP during initial testing so you know which connection the Mac is using.

On supported models, the Thunderbolt connection can also provide a faster network path for the first full Time Machine backup than Wi-Fi. The backup destination and storage quota are still configured through SMB.

How to Confirm the Transfer Is Using Thunderbolt

Connecting the cable does not make an existing mapped share switch from Ethernet to Thunderbolt. A hostname can continue resolving to the NAS’s normal LAN address.

Use the dedicated Thunderbolt IP for the first test:

- Windows: `\169.254.x.x\SharedFolder`
- macOS: `smb://169.254.x.x/SharedFolder`

Start a transfer using one large file of at least 20GB. Small files require more metadata and filesystem operations, making them unsuitable for measuring maximum sequential throughput.

While the transfer is running:

- On Windows, open Task Manager and check the Thunderbolt network adapter under Performance.
- On macOS, open Activity Monitor or Network settings and confirm activity on Thunderbolt Bridge.
- Check UGOS Pro Task Manager for storage, network, processor, and memory activity.
- Repeat the transfer through the normal Ethernet address and compare the results.

If the Thunderbolt adapter remains inactive, the computer is still using the LAN route. Remove the old mapping and reconnect using the explicit `169.254.x.x` address.

Keep the default MTU while establishing this baseline. Jumbo frames require matching MTU support and configuration on both endpoints. Changing only one side can cause stalled or failed transfers.

What Thunderbolt Transfer Speed Should You Expect?

Thunderbolt 4 provides a 40Gbps link, but UGREEN direct connection carries IP and SMB traffic over that link. No single interface figure predicts the resulting file-transfer speed.

The storage behind the connection frequently sets a lower ceiling:

These storage figures are practical reference ranges, not guaranteed UGREEN NAS performance results.

A DXP6800 Pro with an HDD RAID array will not transfer at the same speed as a DXP480T Plus with four fast NVMe SSDs. A faster connection cannot make the storage pool read or write beyond its own limit.

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The client also matters. Copying data from the NAS to a laptop with a slower internal SSD stops at the laptop’s write speed. A high initial result followed by a sharp drop can mean that the client SSD has exhausted its write cache.

Windows and macOS can produce different results because their network and SMB implementations differ. Compare each system against its own Ethernet baseline instead of assuming both platforms will reach the same speed.

For sustained video work, calculate the required throughput from the number of streams and codec bitrate before deciding whether an HDD array or NVMe pool is sufficient. The UGREEN NAS video-editing guide provides the calculation and storage-performance references.

Why Is the Thunderbolt Connection Slow or Unstable?

Start with the symptom before changing RAID settings or buying hardware.

The NAS is not detected

Connect the NAS directly to the computer without a dock or adapter. If another Thunderbolt computer or cable is available, substitute one component at a time.

Proving the physical link first is faster than changing SMB or storage settings before the NAS appears as a network interface.

The share opens, but transfers are slow

Confirm that the share uses the Thunderbolt IP, then test one large file in both directions.

If the network interface reports substantially more throughput than the file copy, the network is not the primary bottleneck. Check:

- Client read and write speed
- NAS storage-pool activity
- Installed drive performance
- RAID rebuilds and data scrubbing
- SMB signing or encryption
- Photo indexing and thumbnail generation
- Docker containers or virtual machines
- Cloud synchronization and backup tasks

If the slowdown also occurs over Ethernet, continue with the broader UGREEN NAS performance troubleshooting guide.

The transfer starts fast and then slows down

A repeatable speed drop after a specific amount of data often points to write-cache exhaustion. Consumer SSDs can write quickly to a temporary cache and slow down after that cache fills.

Heat creates a different pattern. During a sustained transfer, the NAS NVMe drives or the client SSD can reach a temperature that triggers thermal throttling. This is especially relevant to the all-NVMe DXP480T Plus.

Watch drive temperatures while reproducing the slowdown. If performance returns after the drives cool, thermal throttling is likely. If the drop occurs after a similar amount of data during every test, cache exhaustion is the stronger explanation.

The connection fails after sleep

Sleep behavior depends on the computer and operating system.

Some Windows laptops maintain the Thunderbolt connection in a low-power state. Some desktop systems cut power to the interface and do not reconnect it automatically. BIOS options such as ErP Ready, Always On USB, or Thunderbolt Wake Support can affect the result, although their names vary by motherboard.

macOS deep sleep can disconnect Thunderbolt Bridge. If the connection does not return after wake:

1. Open `System Settings > Network`.
2. Confirm that Thunderbolt Bridge still appears.
3. Remove duplicate Thunderbolt Bridge services.
4. Disconnect and reconnect the cable.
5. Reconnect the SMB share using the Thunderbolt IP.

Do not disable operating-system security protections simply to preserve a storage connection during sleep.

Other Thunderbolt devices reduce performance

Several physical Thunderbolt ports on a computer can share the same controller and bandwidth. A dock, display, capture device, external SSD, or eGPU attached to that controller can compete with the NAS connection.

Disconnect nonessential devices while testing. If the computer has ports connected to different Thunderbolt controllers, place the NAS and other high-bandwidth devices on separate controllers.

Should You Use Thunderbolt or 10GbE?

Thunderbolt and 10GbE solve different connection problems.

Choose Thunderbolt direct connection when:

• One workstation needs a dedicated high-speed path.
• The computer and NAS are close enough for a direct cable.
• You want to avoid purchasing a 10GbE switch or computer adapter.
• The workstation regularly transfers large video, photo, or project files.
• Other devices can continue using the NAS through Ethernet.

Choose 10GbE when:

- Several computers need high-speed access.
- The NAS is located in another room.
- The connection must remain available when one workstation sleeps or disconnects.
- The studio already has a 10GbE switch and suitable cabling.
- You want every workstation to use the same network path.

A supported UGREEN NAS can use both connections. Thunderbolt can provide a dedicated path to the primary workstation while Ethernet keeps the NAS available to other users and devices.

Can You Connect an eGPU to UGREEN NAS?

An eGPU attached to the computer is separate from the NAS. It can share the computer’s Thunderbolt-controller bandwidth with the NAS, so simultaneous GPU and storage activity can reduce transfer performance.

Connecting an eGPU directly to the NAS is a different configuration. It requires support for the exact NAS model, GPU enclosure, graphics card, driver, and UGOS Pro application. The Thunderbolt networking procedure in this article does not configure an external GPU.

An eGPU connected to the NAS also does not become available inside Docker or a virtual machine through this setup. GPU passthrough for Docker and Virtual Machine is listed as a planned feature in the UGREEN System Update Plan.

Use Thunderbolt direct connection for high-speed file access. Treat NAS-side GPU deployment as a separate workload with its own hardware and software requirements.

Once the connection is working, test the explicit Thunderbolt IP with one large file. If the Thunderbolt adapter is active but file speed remains low, the storage path, client drive, or active workload is the next place to investigate.