The short answer
You usually don't get to choose. Your motherboard decides which memory you need, because DDR4 and DDR5 sticks don't fit in each other's slots.
- DDR5Building new on AMD AM5 (Ryzen 7000, 8000, 9000) or Intel Core Ultra 200S (LGA 1851). These only take DDR5.
- DDR4Upgrading a PC on AMD AM4 (Ryzen 1000–5000) or older Intel. These only take DDR4.
- EitherIntel 12th–14th gen (LGA 1700) boards were made in both versions. Check your board's model name or manual; each board supports only one type.
Today a 32GB DDR5 kit costs … than 32GB of DDR4. Lowest prices right now: DDR5 from …, DDR4 from ….
Today's price gap
Lowest in-stock kit at any store we track, updated daily| Kit size | DDR4 | DDR5 | DDR5 costs |
|---|---|---|---|
| Loading today's prices… | |||
What's actually different
| DDR4 | DDR5 | |
|---|---|---|
| Typical speeds | 2133–3200 MT/s standard, about 3600 with XMP | 4800–6400 MT/s standard, 6000–8000+ with EXPO/XMP |
| Bandwidth | Baseline | Roughly 1.5–2× at common speeds |
| Channels per stick | One 64-bit channel | Two independent 32-bit sub-channels, so the CPU can handle more requests at once |
| Voltage | 1.2 V (1.35 V for most XMP kits) | 1.1 V (1.25–1.4 V for most EXPO/XMP kits) |
| Power control | On the motherboard | A power chip (PMIC) on each stick |
| Error correction | None on standard desktop sticks | On-die ECC fixes errors inside the chips. This is not the same as full ECC memory. |
| Common stick sizes | 8, 16, 32GB | 16, 24, 32, 48, 64GB |
| Fits the other's slot? | No. Both have 288 pins, but the notch sits in a different place, so a stick physically won't go in the wrong slot. | |
Speed vs. latency: the CL number
Memory kits list two numbers: speed (MT/s) and CAS latency (CL). DDR5's CL numbers look much worse, but they count clock cycles, and DDR5's cycles are shorter. To compare kits, convert to nanoseconds:
true latency (ns) = CL × 2000 ÷ speed
| Kit | True latency | Verdict |
|---|---|---|
| DDR4-3200 CL16 | 10.0 ns | The classic DDR4 sweet spot |
| DDR4-3600 CL18 | 10.0 ns | Same latency, more bandwidth |
| DDR5-4800 CL40 | 16.7 ns | Bare minimum DDR5; skip it if a faster kit costs about the same |
| DDR5-6000 CL30 | 10.0 ns | Same latency as good DDR4, with nearly twice the bandwidth |
| DDR5-6400 CL32 | 10.0 ns | Slightly more bandwidth; runs best on newer CPUs |
The cheapest 32GB DDR5-6000 CL30 (or faster) kit today is …. The cheapest 32GB DDR4-3200 CL16 (or faster) kit is ….
Does it matter for gaming?
Less than the graphics card, and less than the CPU. Faster memory helps most when the CPU is the bottleneck: high frame rates at 1080p, big strategy and simulation games, and esports titles. At 1440p and 4K the graphics card usually sets the pace, and memory speed barely shows.
Outside games, DDR5's extra bandwidth helps memory-heavy work such as video editing, file compression, compiling code and running large spreadsheets or local AI models.
Bottom line: don't throw out a working DDR4 system to get DDR5. Do pick a good DDR5 kit (6000 CL30) when building on a new platform, because that's what those CPUs are tuned for.
Buying tips
- 32GB (2×16GB) is the sweet spot for gaming. 16GB still works for light use. Go to 64GB for heavy editing, many browser tabs plus games, or virtual machines.
- Buy a matched kit of two sticks. Two sticks run in dual-channel mode. Mixing kits, or filling all four slots with DDR5, often forces lower speeds.
- Turn on the speed profile. Kits run at a slow default until you enable EXPO (AMD) or XMP (Intel) in the BIOS. Either profile usually works on either brand.
- For AMD AM5, aim for DDR5-6000 CL30. Much faster kits cost more for little gain on these CPUs.
- Check the board's memory support list (QVL) if you're buying large or very fast kits.
- Laptop memory is different. Laptops use smaller SO-DIMM sticks; everything listed on LowestBin is desktop memory.