UGREEN CM847 USB4 2-Bay M.2 NVMe SSD Enclosure with Offline Clone & RAID – 40Gbps Dual NVMe Storage Dock (65733EU)
UGREEN CM847 USB4 2-Bay M.2 NVMe SSD Enclosure with Offline Clone &...
Overview
UGREEN CM847, model 65733EU, is a desktop USB4 enclosure for two compatible M.2 NVMe solid-state drives. It can present installed storage to a computer for high-speed work and can also perform an offline clone from the bay marked Source to the bay marked Target.
What it does well.
Key features
At a glance
Two drive bays, one USB4 host path and dedicated controls
Port-by-port clarity
Bay A / Source. Install the source M.2 NVMe drive here for offline cloning only after confirming the label on the unit.
Bay B / Target. The target receives the clone and can be overwritten. Confirm capacity and identity before starting.
USB4 host connection. Links the enclosure to a compatible computer at up to the mutually negotiated rate, with 40Gbps as the interface maximum.
Mode and clone controls. Use only according to the printed labels/manual; do not change a RAID-style mode while data is mounted or unprotected.
Offline cloning is directional and destructive to the target
Clone workflow
this product image labels bay A as Source and bay B as Target. Offline cloning copies the source drive onto the target without using a computer data session. It is not a bidirectional merge, selective file copy or backup that preserves existing target data.
Before starting, identify both drives outside the enclosure, confirm that the target is appropriate for a full-device copy and keep a separate backup. Do not remove power, press mode controls or disturb either drive until the device reports completion according to its indicator sequence.
- Source data is copied to Target, not the reverse.
- Existing target data can be overwritten.
USB4 bandwidth and active cooling support sustained storage work
Thermal and link management
The aluminium shell spreads heat while an active fan moves air through the enclosure. NVMe drives can still throttle when controller temperature rises, especially during a full clone or long write, so keep the vents uncovered and allow the unit to cool before handling internal drives.
The 40Gbps label describes the host interface. It is not a guaranteed single-drive or file-copy speed and cannot override the SSD, host, filesystem or cable. Test performance with the included/cable and a direct compatible host port before adding adapters.
- Keep inlet and outlet vents clear.
- Eject mounted volumes before disconnecting USB4.
Use scenarios
Real-world applications
Choose this model when its connections and limits match the workflow below.
Dual-drive workspace. Access two compatible NVMe SSDs from one USB4 host for organised project and scratch storage.
Offline migration. Clone a complete source SSD to an appropriate target without using a computer data session.
Media scratch storage. Use fast external NVMe media for high-throughput project files when the host, cable and SSDs support the workload.
Bench verification. Install and test compatible NVMe drives while monitoring identity, temperature and health before deployment.
Setup and usability guidance
Practical connection order
A deliberate connection order makes capability checks and troubleshooting easier.
- Record the model as CM847 / 65733EU and read the manual before opening the enclosure.
- Back up all data on any drive that will be installed.
- Verify each SSD interface, key, dimensions and intended source/target role.
- Disconnect host data and power before installing or removing drives.
- Fit drives and any thermal interface parts without bending the module.
- For computer access, connect directly to a compatible USB4 host and allow the OS to detect the storage.
- For offline clone, confirm A/Source and B/Target, then follow the button and indicator sequence without interruption.
Compatible devices and systems
Host and peripheral fit
Connector shape alone is not enough: the host port, operating system, cable, display and peripheral must support the required function.
USB4 computers. Compatible Windows, macOS or Linux systems with USB4-class data support offer the highest stated interface ceiling.
Fallback USB-C links. A slower compatible USB-C data host may negotiate a lower rate; connector shape does not guarantee 40Gbps.
M.2 NVMe drives. Use only compatible NVMe SSDs that match the enclosure key, interface and supported dimensions stated in its manual.
Filesystems and RAID. The operating system must support the chosen disk format or array presentation; initialization may be required for new drives.
What this product does
Function scope
- Houses two compatible M.2 NVMe SSDs in one USB4 desktop enclosure.
- Provides a host interface rated up to 40Gbps.
- Performs an offline one-touch clone from the labelled source bay to target bay.
- Offers RAID capability when configured according to the unit manual.
What this product does not do
Boundaries that prevent a mismatch
- It does not include either SSD.
- It does not make a SATA M.2 drive compatible merely because it fits physically.
- It does not guarantee 40Gbps application or file speed.
- It does not preserve existing target data during a full offline clone.
What to do
Recommended practice
- Keep an independent backup before clone or RAID operations.
- Label source and target drives before installation.
- Use a direct compatible USB4 host connection for performance testing.
- Keep fan vents clear and place the enclosure on a hard surface.
What not to do
Avoid common mistakes
- Do not guess the RAID mode or change a switch while volumes are mounted.
- Do not reverse Source and Target during offline cloning.
- Do not remove power during a clone, rebuild or write.
- Do not install an unverified SATA M.2 drive.
Warnings and limitations
Read before use
Check before connecting or ordering.
Warning / limitation 1. Offline cloning can irreversibly overwrite the target drive.
Warning / limitation 2. Changing storage mode can require reinitialization and can make existing data inaccessible.
Warning / limitation 3. An NVMe SSD can become hot during sustained writes; allow cooling before handling.
Warning / limitation 4. USB4 performance varies with host, cable, SSD, filesystem, thermals and simultaneous drive activity.
- The live variant SKU field is blank; match CM847 and 65733EU on the title, enclosure or retail package.
- SSDs are not included.
- Use M.2 NVMe drives only; do not assume a physically similar SATA M.2 drive is supported.
- Verify supported key, length, capacity and any required thermal pad in the manual before installation.
- Offline clone is Source-to-Target and can overwrite the entire target.
- Back up both drives before any mode change, initialization or cloning operation.
At a glance.
- Brand / model
- UGREEN CM847 / 65733EU
- Product type
- Dual-bay M.2 NVMe SSD enclosure / storage dock
- Host interface
- USB4, up to 40Gbps
- Drive bays
- 2 × M.2 NVMe
- Offline clone
- One-touch Source A to Target B
- RAID
- RAID capability; modes and switch sequence must be checked in the unit manual
- Cooling
- Active fan plus aluminium enclosure
- Included storage
- None; SSDs not included
- Host requirement
- Compatible USB data host; USB4-class host/cable required for the stated interface ceiling
- Data safety
- Backup required before clone, mode change or initialization
- In the box
- 1 × UGREEN CM847 / 65733EU dual-bay USB4 NVMe enclosure.
1 × USB-C host cable as shown with this product.
Drive-installation parts and documentation only as supplied with the retail unit.
Model-specific data
In-box information
No M.2 NVMe SSD is included. Screws, thermal pads, power equipment and manual contents should be checked against the sealed regional package before installation; the current record does not safely enumerate them.
Questions buyers ask.
Are SSDs included with CM847?
No. The enclosure is supplied without SSDs.
Does it support SATA M.2 drives?
this product is described for M.2 NVMe. Do not install a SATA M.2 drive unless the manual explicitly lists it.
Will every USB-C port run at 40Gbps?
No. The host and cable must support a USB4-class link. A slower compatible port negotiates a lower rate.
Is 40Gbps the file-copy speed?
No. It is the host-interface maximum. SSD, bridge, host, filesystem, files and temperature determine practical performance.
Which direction does offline clone run?
media labels bay A as Source and bay B as Target. Confirm those labels on your unit before starting.
Will offline clone preserve files already on the target?
No. Treat the operation as destructive to the target and keep a separate backup.
Can I clone a larger source to a smaller target?
Do not assume so. A full-device clone normally requires an appropriate target capacity; confirm the manual before starting.
Which RAID modes are supported?
The product advertises RAID capability, but this description does not guess the mode matrix. Follow the labels and manual supplied with CM847.
Why is a new SSD not visible in the operating system?
It may need initialization, or the drive/interface may be incompatible. Verify the disk identity and enclosure support before formatting anything.
Does the fan prevent all thermal throttling?
No. Active cooling helps, but sustained transfers, ambient temperature and SSD design can still reduce speed.
Is RAID a backup?
No. RAID can change capacity or availability characteristics, but it does not replace a separate, copy of important data.
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Warranty
Country of Origin: China
Manufactured by: UGREEN Group Limited
Imported & Marketed by: Sophus Technosol Private Limited, Durga Complex, 2nd Floor, #38/1, 3rd Cross, Sahakarnagar G Block, Bengaluru – 560092, Karnataka, India
Customer care: +91 94038 93363 (phone / WhatsApp) · info@ugreenindia.com · Mon–Sat, 10:30–18:00 IST
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