DDR5-6000 CL30 vs DDR5-8000 CL38: faster clocks or tighter latency?
On AMD, choose DDR5-6000 CL30 — the 1:1 fabric coupling makes it the faster, cheaper, more reliable pick. On Intel Arrow Lake and newer, DDR5-8000 CL38 is the better kit if your board and IMC support it, delivering both more bandwidth and slightly lower effective latency.
The kit that looks slower on paper often wins on AMD — and loses on Intel.
On the spec sheet, DDR5-8000 CL38 wins both metrics: 9.5 ns first-word latency (vs 10.0 ns for DDR5-6000 CL30) and 64 GB/s of per-channel bandwidth (vs 48 GB/s). But raw timing math ignores the single biggest real-world factor: whether the memory controller runs in a coupled 1:1 mode or a decoupled 2:1 gear, which can swing effective latency by more than the timings ever do.
By TechCompare · Updated
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True latency, converted to nanoseconds
By the timings alone, DDR5-8000 CL38 is both lower latency and higher bandwidth. The catch the numbers can't show: on AMD AM5 it runs in 2:1 gear, which adds real latency that flips the result in games. On Intel gear-2 platforms, the on-paper win holds.
DDR5-6000 CL30
First-word latency
↑ 5.3% higher latency
Peak bandwidth / channel
DDR5-8000 CL38
First-word latency
↓ 5.0% lower latency
Peak bandwidth / channel
Latency = CAS (CL) × clock-cycle time. Higher MT/s shortens the cycle, looser CL lengthens the cycle count — the nanosecond figure is what actually reaches the CPU.
Tune your own timings? Open the RAM Latency Calculator
Side-by-side specs
| Spec | DDR5-6000 CL30 | DDR5-8000 CL38 |
|---|---|---|
| Data rate | 6000 MT/s | 8000 MT/s (better on this spec) |
| First-word latency (timings) | 10.00 ns | 9.50 ns (better on this spec) |
| Peak bandwidth / channel | 48 GB/s | 64 GB/s (better on this spec) |
| AMD AM5 mode | 1:1 (UCLK=MCLK) (better on this spec) | 2:1 gear (penalty) |
| Effective latency on AMD | Lowest (better on this spec) | Higher (gear 2) |
| Intel Arrow Lake mode | Gear 2 | Gear 2 (native) (better on this spec) |
| Effective latency on Intel | Higher | Lower (better on this spec) |
| IMC / board demand | Low (better on this spec) | High (strong IMC) |
| Stability / ease of POST | Very easy (better on this spec) | Tuning often needed |
| Relative price | Lower (better on this spec) | Higher |
| Best for AMD gaming | Yes (better on this spec) | No |
| Best for Intel productivity | Capable | Best (better on this spec) |
How they differ
On AMD AM5 (Ryzen 7000/9000), DDR5-6000 is the sweet spot because it lets the memory clock, Infinity Fabric, and controller run 1:1 (UCLK=MCLK with FCLK around 2000 MHz). Pushing to 8000 forces a 2:1 gear that adds latency and often won't post stably, so 6000 CL30 is usually faster in games despite the worse on-paper numbers. On Intel (Arrow Lake / Core Ultra 200S), the controller is built for higher gear-2 speeds, so DDR5-8000 CL38 genuinely pulls ahead in both bandwidth and effective latency. The kits also differ in price and stability: 8000 CL38 demands a strong IMC, a 2-DIMM board, and good cooling, while 6000 CL30 runs almost anywhere.
Verdict
On AMD, choose DDR5-6000 CL30 — the 1:1 fabric coupling makes it the faster, cheaper, more reliable pick. On Intel Arrow Lake and newer, DDR5-8000 CL38 is the better kit if your board and IMC support it, delivering both more bandwidth and slightly lower effective latency.
See DDR5-6000 CL30 latencyWhich should you pick?
Choose DDR5-6000 CL30
Pick DDR5-6000 CL30 for any AMD Ryzen 7000/9000 build, for two-stick simplicity, and any time guaranteed stability matters more than chasing benchmark bandwidth. It's the safest high-performance DDR5 kit you can buy.
See DDR5-6000 CL30 latencyChoose DDR5-8000 CL38
Pick DDR5-8000 CL38 on Intel Arrow Lake / Core Ultra platforms with a capable IMC and a 2-DIMM motherboard, where gear-2 is the norm and the extra 33% bandwidth is free performance for productivity and high-refresh gaming.
See DDR5-8000 CL38 latencyRelated comparisons
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