Guide · CPU Guides · Updated Sep 23, 2026 · 4 min read

DDR4 vs DDR5: which memory does your build need?

Current AMD and Intel desktop platforms take DDR5 only. Where DDR4 still fits, how DDR5 differs inside, what the speed and timing numbers mean, which speed to buy, and why memory costs so much in 2026.

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For a new AM5 build (Ryzen 7000, 8000 and 9000) or LGA1851 build (Core Ultra 200S), the choice is made for you: both platforms take DDR5 only. DDR4 is still an option on older platforms: AMD AM4 is DDR4 only, and Intel LGA1700 (12th–14th gen Core) boards come in DDR4 and DDR5 versions. The two don’t fit each other’s slots. The key notch sits in a different place, and a board takes one or the other, never both.

DDR5 is required on current platforms

If you’re buying a new CPU and motherboard, buy DDR5. If you’re reusing parts, check the memory type on the motherboard’s spec page before ordering anything. This matters most on LGA1700, where two boards with the same chipset can take different memory. The part picker checks memory type against the board and CPU for you.

What changed inside DDR5

Two sub-channels per stick. Each DDR5 stick is split into two independent 32-bit sub-channels, so the memory controller can handle more requests at once. A two-stick kit is still “dual channel” in the way that matters for buying.
Power management on the stick. DDR5 modules carry their own power management chip (PMIC) instead of relying on the motherboard for memory voltage.
On-die ECC isn’t ECC memory. DDR5 chips correct some errors inside the chip itself, which makes denser chips reliable enough to make. It doesn’t protect data on its way to the CPU, so it’s not the same as the ECC memory used in servers and workstations.
Bigger sticks. DDR5 made 24 GB and 48 GB modules common, so 48 GB and 96 GB kits exist alongside 32 GB and 64 GB.

Speed, bandwidth and timings

Memory speed is given in megatransfers per second (MT/s), often labelled MHz on the box. Peak bandwidth is the speed times 8 bytes per channel, and desktop CPUs have two channels:

DDR4-3200 in dual channel: 51.2 GB/s
DDR5-6000 in dual channel: 96 GB/s

Timings measure delay. To compare kits, convert CAS latency (CL) to nanoseconds: CL × 2000 ÷ speed. DDR4-3200 CL16 and DDR5-6000 CL30 both work out to 10 ns. So DDR5 brings much more bandwidth at about the same latency. Games that are limited by the CPU benefit most; games limited by the graphics card barely notice.

Which DDR5 speed to buy

AMD Ryzen 9000: AMD guarantees DDR5-5600 with two sticks. DDR5-6000 is the usual pick because the CPU’s memory controller runs at the same clock as the memory (1:1) on practically every chip at that speed. Many Ryzen 9000 CPUs also manage DDR5-6400 at 1:1, but it isn’t guaranteed. Much faster kits push the controller to half speed and gain little in games.
Intel Core Ultra 200S: DDR5-6400 is the official speed. The platform also supports CUDIMM kits, which carry their own clock driver chip to run faster; they need a board that supports them.
Two sticks, not four. Four sticks run much slower. On Ryzen 9000, AMD’s official speed drops to DDR5-3600 with four sticks.
Turn on the profile. Every kit runs at a slower default speed until you enable its XMP or EXPO profile in the BIOS. See BIOS setup.

A kit that matches the AMD recommendation: G.Skill Flare X5 32GB DDR5-6000 CL30.

Where DDR4 still makes sense

Upgrading an AM4 or DDR4 LGA1700 PC. A new CPU on the same board keeps your existing memory, which is the biggest saving available in 2026.
Reusing parts in a budget build. If you already own a DDR4 kit, an AM4 build can use it. DDR4 prices have risen too, so this helps only if you have the memory already.

For a brand-new build you intend to upgrade over several years, AM5 or LGA1851 with DDR5 is the platform with a future.

What memory costs in 2026

Memory prices have risen sharply since late 2025, as manufacturers moved production to high-bandwidth memory for AI servers. Tom’s Hardware tracked 32 GB DDR5-6000 kits at around $400 in August 2026, against roughly $90 a year earlier, and DDR4 has climbed too. Deciding how much to buy? See how much RAM you need.