Upgrade your Cisco UCS C240 M3 RAM

What Types of RAM Are Supported in the Cisco UCS C240 M3?

• The Cisco UCS C240 M3 supports RDIMM (Registered DIMMs), LRDIMM (Load-Reduced DIMMs) and UDIMM (Unbuffered DIMMs).

Which Memory Speeds Are Compatible With the Cisco UCS C240 M3?

• The server supports DDR3-1333, DDR3-1600, DDR3-1866.
• Keep in mind that if different speeds are mixed, all modules operate at the slowest DIMM speed.

What Is the Maximum Supported RAM Capacity for the Cisco UCS C240 M3?

• Up to 384GB (24 × 16GB) with RDIMMs.
• Up to 768GB (24 × 32GB) with LRDIMMs.
• Up to 96GB (16 × 4GB) with UDIMMs.

How do I achieve the best performance for my Cisco UCS C240 M3?

• Populate DIMMs evenly across all channels and use the highest supported speed compatible with your CPU.

What is RDIMM, LRDIMM, UDIMM?

• RDIMM (Registered DIMM): Registered DIMMs are memory modules with an additional register between the memory controller and the DRAM. This register reduces the electrical load on the memory controller, allowing for better stability and scalability in servers. RDIMMs are commonly used in environments that require high reliability and performance.
• LRDIMM (Load-Reduced DIMM): Load-Reduced DIMMs replace the register found in RDIMMs with an on-board memory buffer, further reducing the electrical load on the memory controller. This enables servers to support higher memory capacities compared to RDIMMs. LRDIMMs are ideal for applications requiring maximum memory density and performance.
• UDIMM (Unbuffered DIMM): Unbuffered DIMMs do not include a register or buffer, meaning they communicate directly with the memory controller. While they offer lower latency compared to RDIMMs and LRDIMMs, UDIMMs are typically used in desktops or workstations rather than servers, as they cannot support high memory capacities or intensive workloads.

General DIMM Population Guidelines for Cisco UCS C240 M3

• Do Not Mix RDIMMs, LRDIMMs and UDIMMs
• If mixing memory speeds, all DIMMs will operate at the lowest speed.
• Install DIMMs starting furthest from the processor.
• Populate DIMMs evenly across all channels.
• Ensure all CPUs have memory installed for their DIMM slots to function.

Cisco UCS C240 M3 Memory Installation Steps

• Power Off the server and disconnect it from power.
• Wear ESD Gear: Use an ESD wrist strap and work in an ESD-safe environment.
• Open the server and locate the DIMM slots.
• Inspect the slots for dust or debris and ensure proper alignment of the DIMMs.
• Follow the DIMM population order in the server manual.
• Firmly insert DIMMs until they click. Avoid using excessive force.
• Close the server and reconnect power.
• Verify the memory configuration in the BIOS.