Design
Internal
Hot-swap
Features
RAID levels	JBOD
Logistics data
Harmonized System (HS) code	84733020
Other features
Compatibility	SR645, SR665, ST650 V2, SR630 V2, SR650 V2
Packaging data
Quantity	1
Ports & interfaces
Host interface	PCIe
Output interface	PCIe
Expansion card form factor	Low-profile
Expansion card standard	PCIe 4.0
NVMe

The Lenovo ThinkSystem 4-Port PCIe Gen4 NVMe Retimer Adapter, type CTLR, manufacturer number 4C57A65446, is an internal expansion card module for server systems, specifically developed to support NVMe SSDs. The device serves as an interface adapter, transmitting PCIe signals from NVMe drives while stabilizing signal integrity over longer cables or at high data rates. It is designed for use in Lenovo ThinkSystem series servers, particularly in models SR645, SR665, ST650 V2, SR630 V2, and SR650 V2, enabling the connection between the server backplane and NVMe SSDs.

Applications

The adapter is primarily intended for use in enterprise and data center servers where high data rates and reliability are required. It is used to integrate NVMe SSDs into existing server infrastructures, especially when the physical arrangement of drives or cable length could affect signal quality. Support for hot-swap allows for maintenance and drive replacement without system reboot, which is important for critical applications.

Features and Equipment in Detail

The module features a host interface and an output interface compliant with the PCIe standard, with the expansion card supporting the PCIe 4.0 standard. The form factor configuration is executed as Low Profile, meaning the card can be installed in server enclosures with limited space. Support for NVMe enables the use of NVMe SSDs, which are optimized for high IOPS and low latency. The device operates in JBOD mode (Just a Bunch of Disks), meaning it presents individual drives as independent units without RAID overlay or data redundancy.

Technology Explained Simply

A retimer adapter like this performs the task of regenerating the electrical signals of the PCIe connection. Over longer cables or at high data rates, signal distortion can occur, impairing data transmission. The retimer ensures that signals remain clean and stable on the path from the server backplane to the NVMe drive. This is particularly important when drives are not directly connected to the motherboard, but are connected via a backplane or expansion card. The PCIe 4.0 interface supports a bandwidth of up to 16 GT/s per lane, enabling high data rates to be transmitted.

Compatibility and Accessories

The adapter is specifically designed for Lenovo ThinkSystem server models SR645, SR665, ST650 V2, SR630 V2, and SR650 V2. Compatibility is confirmed by manufacturer specifications, with the listed models supporting the physical and electrical interface required for the adapter's operation.

Installation and Mounting

Installation is performed internally within the server enclosure. Due to the Low Profile design, the card fits into standard server slots designed for expansion cards with reduced height. Mounting is done via the PCIe interface, with the hot-swap feature allowing the card to be replaced during operation without shutting down the server. The physical installation type is defined as installed, meaning it is mounted inside the server enclosure and not connected externally.

Operational Advantages

Using the retimer adapter enables the use of NVMe SSDs in servers that do not directly offer a PCIe interface for these drives. Signal regeneration ensures stable data transmission, even over longer cables. The hot-swap function reduces downtime during maintenance. Support for JBOD provides flexibility in drive management, especially in environments where no RAID structure is required. Compatibility with multiple Lenovo server models increases deployment flexibility within existing infrastructures.