Server RAM Prices: DDR5 and DDR4 ECC Compared

What counts as server RAM?

Server RAM is memory built for machines that run around the clock and hold data nobody wants to lose: rack servers, tower servers and many workstations. Kingston says most servers and workstations use registered DIMMs (RDIMMs). A register on the module, the registered clock driver, buffers the signals between the memory chips and the processor, which is how a server reaches large capacities at high speed. RDIMMs also carry extra memory chips for error correction (ECC).

Plenty of people who search for server RAM are not buying for a data centre, though. They want memory for a home server, a NAS, a video workstation or a small office machine, and some of those run on normal desktop modules. This guide sorts out which type you need and puts this week's UK prices for normal kits next to it. For the basics of what memory does, start with what RAM is.

DDR5 or DDR4: which servers take which?

The generation depends on the server platform, not on your budget. Intel's current Xeon 6 line uses DDR5. Intel lists the Xeon 6980P, a 128 core processor launched in 2024, with 12 memory channels, DDR5 at 6400 MT/s or MRDIMM at 8800 MT/s, up to 3TB of memory and ECC support.

Older servers run on the previous generation. Intel lists the Xeon Gold 6338, a 3rd Gen Xeon Scalable chip from 2021, with DDR4 3200, 8 memory channels, up to 6TB and ECC support. A server like that needs DDR4 ECC RDIMMs, and a DDR5 module will not fit, because DDR4 and DDR5 have the notch in a different place.

So the first step is simple: find the exact model of your server or motherboard and read its memory support list. That tells you the generation, the module type and the speeds the maker has tested.

RDIMM, ECC UDIMM or a normal kit?

Three kinds of module turn up when you shop for server memory. They look alike in a photo but they are not interchangeable. The table shows how they differ.

Kingston points out a change that catches people upgrading from DDR4: on DDR5, registered DIMMs and ECC unbuffered DIMMs have different notches. An RDIMM will not go into a board built for unbuffered memory, and the reverse is also true.

On-die ECC causes the other common mix-up. Every DDR5 chip corrects some bit errors inside the chip itself, but it cannot catch errors on the way to the processor. A normal DDR5 kit is therefore not ECC memory in the server sense. Full ECC needs a processor with ECC in its memory controller, a board that enables it and ECC modules. Our ECC RAM guide covers that in more detail.

What server RAM costs in the UK right now

First, what we measure and what we do not. Our weekly price run covers normal desktop and laptop kits at UK shops, currently Amazon.co.uk, AWD-IT, Box, CCL, Laptops Direct, Overclockers UK and Scan. Registered and ECC modules are not part of it, so we cannot give you a live RDIMM or ECC UDIMM price. How the run works is explained on how we track RAM prices.

What we can show is the comparison most workstation and home server buyers need: normal kits in the sizes a server build tends to use. The table lists the cheapest desktop kit per size, the price per GB and the median. Data from 2 November 2026, including VAT.

This week the cheapest 64GB DDR5 kit is the Integral 64 GB (2 x 32 GB) DDR5 4800 at Amazon.co.uk. Change in the median price per GB of 64GB DDR5 kits over the last 4 weeks: not measured yet. Every kit with its current price is on our 64GB RAM prices and 128GB RAM prices pages.

Why server memory is scarce and expensive

Most of the demand comes from cloud providers. TrendForce reports that it is spreading from servers that train AI models to general purpose servers for AI inference and AI agents, and those use standard DDR5 RDIMMs, not only the HBM on AI accelerators. In its 30 September 2026 release, TrendForce said cloud providers and server makers were buying more bits for RDIMMs as server processors became easier to get, and that server DRAM stays undersupplied in the fourth quarter of 2026.

Memory makers follow the margin. TrendForce says suppliers keep shifting capacity to server products because margins are higher there, and that PC DRAM supply could shrink in 2027 as a result. The price moves have been extreme: in February 2026 TrendForce expected server DRAM contract prices to rise around 90% quarter on quarter in the first quarter of 2026, the largest quarterly increase it had recorded. Those are contract prices between memory makers and large buyers, not shop prices.

The outlook is not much easier. TrendForce expects server DRAM contract prices to keep rising every quarter from the second half of 2026 to the second half of 2027, at a slower pace, and estimates that RDIMM bit supply grows only 15% to 20% in 2027, behind server processor shipments. Both are forecasts. For a UK business that has to expand an RDIMM server, they suggest not planning around a quick price drop.

A workstation or home server on normal RAM

Many machines sold as small servers or workstations run on an ordinary AMD AM5 or Intel desktop platform, and those take normal unbuffered DDR5. Newegg puts 64GB at the level for serious video editing, 3D rendering, large datasets and local AI models, which is exactly the workload behind most workstation searches. Unsure about the size? Read how much RAM you need first.

Buy the capacity as a two module kit where you can. AMD lists the Ryzen 9 9950X at DDR5 5600 with two modules and DDR5 3600 with four, so a 128GB build from four 32GB sticks runs much slower at AMD's guaranteed spec than a two stick kit.

If you want ECC on such a machine, you need ECC UDIMMs and a platform that switches ECC on. Kingston sells DDR5 ECC UDIMMs in its Server Premier line at 5600 MT/s in 16GB, 32GB and 48GB modules. AMD lists ECC support for the Ryzen 7 9800X3D as requiring motherboard support. On the Intel side, Tom's Hardware reported in 2022 that 12th Gen Core processors support ECC when paired with a W680 board.

A NAS is its own case. QNAP lists a maximum of 8GB (2 x 4GB) for the TS-453D, warns that unsupported modules can cause errors or stop the system from starting, and recommends its own modules. For a NAS, the maker's list matters more than any price table.

DDR4 ECC server RAM: still worth buying?

For a server that already runs DDR4 there is no alternative: it needs DDR4, and the right type for it, registered or unbuffered. Match the modules already installed in type, speed and capacity. For a new build, DDR5 is the platform with a future.

DDR4 supply is shrinking. Samsung, SK hynix and Micron all announced in 2025 that they would end DDR4 to move capacity to DDR5, LPDDR5 and HBM, and Micron sent official end of life notices to customers in June 2025. TrendForce wrote that server DDR4 orders from cloud providers then crowded out PC and consumer DDR4 supply. Normal DDR4 kits with this week's prices are on our DDR4 RAM prices page.

What we do not know yet

We do not know what an RDIMM or ECC UDIMM costs in UK shops this week. Those modules are not in our weekly price run, so we have no figures of our own, and it is not yet decided whether we will add them.

We also do not know how far the server DRAM squeeze reaches the shop price of ECC UDIMMs for workstations. TrendForce reports on server DRAM and RDIMMs, not on unbuffered ECC modules.

Finally, we have not checked which chipsets for the newest Intel Core Ultra processors actually enable ECC. For any specific board or server, its own specification sheet remains the only reliable source.