DDR5 buying math

Pay $120 more for 2 nanoseconds?

CL30 vs CL36 looks big on the box. The real difference is 2 nanoseconds.

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What CL really is

CAS latency counts cycles, not time

CL is how many clock ticks the RAM waits before answering. Ticks get faster with speed.

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The one-line formula

ns = 2000 x CL / MT/s

True latency in nanoseconds. DDR5-6000 CL30: 2000 x 30 / 6000 = 10.0 ns.

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CL30 vs CL36 at 6000

10.0 ns versus 12.0 ns

Same speed, different CL: the whole debate is about 2 nanoseconds of wait time.

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The tie surprise

7200 CL36 is also 10.0 ns

So is 6400 CL32. A higher CL on a faster kit can match a lower CL exactly.

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What 2 ns buys in games

Roughly 1-4% average FPS

Only when CPU-bound, and benchmarks disagree. Smoother 1% lows are the steadier win.

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Price check, Aug 11, 2026

The CL30 premium: $120

G.Skill CL30 $599.99 vs CL36 $479.99. A Patriot CL30 kit: $429.99. Shop across brands.

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The EXPO/XMP gotcha

Your CL30 may be running CL40

Kits boot at JEDEC defaults until you enable EXPO or XMP in BIOS. Check yours today.

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The X3D exception

Big cache blunts CL

On 7800X3D-class CPUs, the stacked cache blunts CL gains. Buy CL36 and save.

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The verdict

Small delta: yes. Upgrade: no.

Compare your two kits in real nanoseconds - presets loaded, math done for you.

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Compare in nanoseconds