Premium DDR3 Server Memory Solutions

DDR3 server module types and voltages

DDR3 server memory comes as registered, load-reduced and ECC unbuffered DIMMs, and each type can come in a low-voltage DDR3L version. Micron describes its 1.35V DDR3L devices as a low-voltage version of 1.5V DDR3 that is backward compatible to 1.5V operation, and Dell's PowerEdge R720 supports both voltage specifications but lists lower top speeds at 1.35V: one registered DIMM per channel runs at up to 1866 MT/s at 1.5V and up to 1600 MT/s at 1.35V.

Bandwidth is the transfer rate times eight bytes, and it is the figure in the PC3 bandwidth names, so PC3-12800 is DDR3-1600. Intel lists DDR3 for the Xeon 5600 family across three memory channels and for the E5-2600 v2 family across four.

DDR3 limits on a 12th-generation PowerEdge

Dell's PowerEdge R720 manual caps how many DDR3 modules of each type a memory channel takes:

• Up to two ECC UDIMMs per channel.
• Up to three single- or dual-rank RDIMMs per channel, or up to two quad-rank RDIMMs.
• Up to three LRDIMMs per channel, whatever their rank.
• No LRDIMMs on an R720xd with 3.5-inch drives, because of thermal limits.

The same manual rules out mixing UDIMMs, RDIMMs and LRDIMMs in one server, so match the type already installed. These servers take Xeon E5-2600 and E5-2600 v2 processors; see Xeon E5-2600 v2 processors. For DDR4 servers, see DDR4 memory; DDR2 and FB-DIMM modules are under other memory, every generation is on server memory, and ECC is covered in our guide ECC vs non-ECC memory.

DDR3 ECC RAM questions

Can DDR3 ECC server RAM be used in a desktop?

Registered DDR3 cannot. Per Micron, registered modules suit only boards that support registered memory, such as server boards, and do not work where unbuffered DIMMs are expected, as they are on desktops. DDR3 ECC unbuffered modules are a separate class and need a board that lists ECC UDIMM support. Check the module type on the label before reusing server memory elsewhere.

DDR3 vs DDR3L: what is the difference?

Voltage. DDR3 runs at 1.5V, and DDR3L is Micron's 1.35V low-voltage version that is backward compatible to 1.5V operation. A server that supports both, such as Dell's R720, can run DDR3L at the lower voltage but lists lower top speeds there, 1600 MT/s at 1.35V against 1866 MT/s at 1.5V for one registered DIMM per channel.