DDR3 was the memory standard for a long and very widely deployed run of Xeon platforms: the Xeon 5500 and 5600 series, then the E5-2600 and E5-2600 v2 families. That puts it inside Dell PowerEdge 11th and 12th generation servers such as the R710, R620 and R720, HPE ProLiant G7 and Gen8 models including the DL380p Gen8, and Lenovo System x M4 machines. Plenty of those are still doing honest work in racks and comms cupboards, and refurbished DDR3 RAM is the cheapest way to give them more headroom or keep a matched spare on the shelf. The notes below cover what the range includes and how to pick modules your board will actually accept.
At a glance
Typical deployments
Virtualisation hosts
On an older hypervisor, capacity runs out long before CPU does. A dual-socket Gen8 ProLiant or 12th-generation PowerEdge typically offers 24 DIMM slots, and filling them with 16GB dual-rank RDIMMs such as the Hynix HMT42GR7BFR4C-RD takes a host to 384GB. Three DIMMs per channel will lower memory speed on most of these platforms, and for VM density that trade is nearly always worth making. If you need to go beyond what RDIMMs allow, 32GB quad-rank LRDIMMs like the Samsung M386B4G70DM0-CMA reach larger totals; just keep them out of servers already running RDIMMs. Our VMware and Hyper-V buying guide covers how to size RAM per host.
Database and application servers
Here bandwidth and latency matter more than raw gigabytes. E5-2600 processors have four memory channels per socket, so populate all four with one identical DIMM each before adding a second per channel. Buy to the fastest speed the CPU supports: E5-2600 v2 parts can use 1866MT/s, while first-generation E5-2600 chips stop at 1600MT/s. A 16GB PC3-14900R module such as the Micron MT36JSF2G72PZ-1G9 is a sensible default for either, since it simply clocks down on the older processor.
Like-for-like spares on HPE estates
When a ProLiant flags a failed DIMM, the lowest-risk replacement matches its neighbours on capacity, rank and speed. HP-labelled modules such as the Kingston 16GB PC3-10600R (HP 647653-081) and the Hynix 8GB 2Rx4 (HP 647650-071) carry the same spare numbers you will find on the original modules' labels, which makes ordering a direct swap straightforward. Keeping one or two matched spares per server is cheap insurance on hardware this age.
Storage, ZFS and lab builds
ECC earns its keep in a file server, because RAM is caching data on its way to and from disk, and ZFS uses spare memory as its read cache. Prioritise total capacity and full channel population over speed. 8GB single-rank RDIMMs such as the Samsung M393B1G70BH0-CK0 are an inexpensive way to fill every channel on a home lab, test rig or NAS built from a decommissioned server, and single-rank modules leave more headroom for higher DIMM counts per channel.
Why buy from Compuwyze
- Every memory module comes with a 12-month return-to-base warranty; the warranty terms set out how claims work.
- Orders for simple items such as RAM placed before 2pm are aimed to ship the same day.
- UK delivery is normally next working day once your order has shipped.
- Free UK delivery on orders over £50, so a set of matched DIMMs usually ships at no extra cost.
- Returns accepted within 30 days, with return shipping paid by the customer.
- International orders go via FedEx economy or priority services, usually arriving in 2 to 5 days.
DDR3 memory FAQs
Can I use DDR3 in a DDR4 server, or the other way round?
No. DDR3 modules have 240 pins and DDR4 has 288, the key notch sits in a different place and the operating voltages differ, so neither will seat in the other's slot. The memory generation is fixed by the processor and motherboard: Xeon 5500, 5600, E5-2600 and E5-2600 v2 platforms use DDR3, and E5 v3 onwards uses DDR4.
Is server RAM the same as desktop RAM, and what does ECC actually do?
Not quite. Server modules add ECC, an extra chip's worth of data width that lets the memory controller detect and correct single-bit errors on the fly, and registered or load-reduced modules add a buffer that lets a server carry far more DIMMs than a desktop board. Most consumer motherboards will not run registered memory, and most servers will not run desktop non-ECC modules.
Can I mix different DDR3 modules in the same server?
Never mix RDIMMs and LRDIMMs, and do not mix registered modules with unbuffered ones. Within registered memory, different speeds will work but every module runs at the speed of the slowest, and mixing brands of the same specification is generally fine. For predictable results, keep capacity and rank identical within each channel and populate both sockets symmetrically.
Is 8GB of DDR3 enough, or should I buy 16GB modules?
That depends on slot count rather than any single module. 8GB DDR3 sticks suit storage boxes, light application servers and labs where filling every channel cheaply matters most. For virtualisation or anything memory-hungry, 16GB modules give you twice the capacity from the same slots, which saves you from running three DIMMs per channel and losing speed.
What speeds does DDR3 server memory run at? Can it reach 2400MHz?
Registered DDR3 for servers runs at 1333, 1600 or 1866MT/s (PC3-10600, PC3-12800 and PC3-14900). Figures above that belong to overclocked desktop kits, not server memory. In practice your server sets the final speed from the processor model and the number of DIMMs per channel, so a 1866 module may well run at 1600 or 1333.
I have a specific part number. How do I find an equivalent?
Read the specification rather than chasing an exact code. Samsung numbers like M393B1G70QH0-YK0 or M393B1G73QH0-YK0, Hynix codes such as HMT351R7BFR4C-H9 or HMT351R7BFR8A-H9, and Micron parts like MT9JSF25672AZ-1G9K1 all encode capacity, rank, chip width, module type and speed, and that information is usually printed on the label too. OEM numbers such as HPE 672612-081 or IBM and Lenovo 43X5318 and 78P0639 are modules from those same chipmakers relabelled for a server vendor. Match type, capacity, rank and speed and you have an equivalent; note that Micron codes with AZ in that position are unbuffered ECC modules, which cannot share a server with registered DIMMs.