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 a lot of data: rack servers, tower servers and many workstations. According to Kingston, most servers and workstations use registered DIMMs (RDIMMs). A registered clock driver on the module buffers the signals between the DRAM chips and the CPU, which lets a server reach higher capacities and speeds than a desktop board can.

In practice, many people who search for server RAM are not filling a data center rack. They are speccing a video or 3D workstation, a home lab box or a small office server, and some of those run on the same modules as a gaming PC. This guide sorts out which type your machine needs and puts this week's US prices next to the options we track. If you want the basics first, our guide to what RAM is and how it works covers them.

RDIMM vs ECC UDIMM vs regular desktop kits

Three kinds of modules show up when you shop for server memory. They look almost the same in a product photo, but they do not swap freely. The table below shows how they differ.

A regular unbuffered module is 64 bits wide. ECC modules add DRAM chips for the extra data width: 72 bits on DDR4, and 72 bits (EC4) or 80 bits (EC8) on DDR5. Kingston points out a change from DDR4: DDR5 RDIMMs and ECC UDIMMs have different key notches, so a registered DDR5 module does not fit a board built for unbuffered memory, and the reverse is also true.

Every DDR5 chip also has on-die ECC, which fixes bit errors inside the chip. It does not catch errors on the way to the CPU, so a regular DDR5 kit does not give you the error protection a server relies on. Full ECC needs a CPU with ECC in its memory controller, a motherboard that enables it and ECC modules. Our ECC RAM guide covers that in more detail.

Server RAM prices: what our US data covers

Our weekly price run tracks regular desktop and laptop kits at Adorama, Amazon.com, B&H Photo, Best Buy, Corsair.com, Newegg and Walmart. Registered and ECC modules are not part of it, so we do not publish our own RDIMM or ECC UDIMM prices. The details are on how we track prices.

What we can give you is the comparison most workstation and home server buyers need: the price of regular kits at the capacities those builds use. The table shows the cheapest desktop kit and the median price per kit for each size, as of November 2, 2026, excluding sales tax.

The cheapest 128GB DDR5 kit this week is the Kingston Fury Beast 128 GB (4 x 32 GB) DDR5 5200 CL40 at Newegg. Change in the median price per GB of 128GB DDR5 kits over the last 4 weeks: not measured yet. Our 128GB RAM prices page lists every kit at that size, and the 64GB RAM prices page does the same one size down.

If you buy server modules abroad, note that the US cut the duty free limit for small shipments from $800 to $50 on 29 August 2025, according to trade compliance firm AEB. Duties on imported memory modules depend on more than that limit, so check the rules for your shipment before you order.

DDR5 server RAM or DDR4?

For a new server or workstation, DDR5 is the default. The current desktop platforms that many workstations are built on, AMD AM5 and Intel Core Ultra 200S, only take DDR5. A DDR4 module also cannot go into a DDR5 slot, because the key notch sits in a different place.

DDR4 still makes sense in one case: you already own a DDR4 server or workstation and want to add memory. Then buy the same kind of module that is already installed, registered or unbuffered, with or without ECC, ideally at the same speed and capacity.

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

Why server memory stays expensive

Demand for server memory comes mostly from cloud providers. TrendForce says that demand is spreading from AI training servers to general purpose servers for AI inference and agentic AI, which use standard DDR5 RDIMMs rather than only the HBM on AI accelerators. Memory makers keep moving capacity to server products because margins are higher there.

The contract price jumps were large. In February 2026 TrendForce forecast that server DRAM contract prices would rise around 90% quarter over quarter in the first quarter of 2026, the largest quarterly increase it had on record. These are prices between memory makers and big buyers, not shelf prices. In its 4Q26 outlook TrendForce said server DRAM stays undersupplied, held back by component, packaging and testing capacity.

The outlook is not much calmer. According to TrendForce, server DRAM contract prices should go up in each quarter between the second half of 2026 and the second half of 2027, though by smaller steps than before. It also puts the growth of RDIMM bit supply in 2027 at just 15% to 20%, lower than the growth in server CPU shipments. Both are forecasts, not measurements. On the consumer side, Micron left the Crucial consumer business to support larger data center customers, though it still sells Micron branded enterprise memory.

64GB or 128GB for a workstation

Most workstations on AMD AM5 or Intel desktop platforms do not need RDIMMs. Newegg's 2026 sizing guide ties 64GB to heavy work: serious video editing, 3D rendering, big datasets and running AI models locally. 128GB is for people who already run out at 64GB. If you are not sure which size fits, read how much RAM you need first.

Both platforms have room for it. AMD lists up to 256GB for the Ryzen 9 9950X and Intel lists up to 256GB for the Core Ultra 9 285K, both dual channel. The catch is speed. AMD rates the 9950X at DDR5-5600 with two modules but only DDR5-3600 with four. A 128GB build from four 32GB sticks therefore runs far slower at AMD's guaranteed spec than a two stick kit, so a 2 x 64GB kit is the cleaner route where your board supports it.

If you want ECC on a desktop class workstation, you need ECC UDIMMs and a platform that enables them. Kingston sells DDR5 ECC UDIMMs at 5600 MT/s in 16GB, 32GB and 48GB per module. AMD lists ECC support for the Ryzen 7 9800X3D as requiring motherboard support, and Intel brought ECC to 12th gen Core in 2022 when paired with a W680 chipset.

What we do not know yet

We cannot tell you what an RDIMM or ECC UDIMM costs in US shops this week. Those modules are outside our weekly price run, so we have no data of our own on them, and whether we add them later is still open.

We also do not know how much of the server DRAM squeeze reaches the shelf price of ECC UDIMMs for workstations. TrendForce reports on server DRAM and RDIMM contracts, not on unbuffered ECC modules sold at retail.

Finally, we have not verified which motherboard chipsets enable ECC on current Intel Core Ultra processors, or which AM5 boards switch it on. For any specific board, its own spec sheet and memory support list are the only reliable answer.