DDR5 Latency Calculator for True RAM Timing

June 19, 2026

DDR5 Latency Calculator

Convert MT/s and DDR5 timing cycles into clock period, true nanosecond latency, row timing, and practical channel bandwidth.

💾Named DDR5 Kit Presets

⚙Memory Timing Inputs

Data rate (MT/s)

Timing profile source

CAS latency CL (cycles)

tRCD row-to-column (cycles)

tRP row precharge (cycles)

tRAS active-to-precharge (cycles)

Memory channels in use

Effective width per channel

Installed DIMMs

Capacity per DIMM (GB)

Sustained bandwidth efficiency (%)

Controller overhead (ns)

Compare against baseline kit

Latency formulas use DDR memory clock period: 2000 divided by MT/s. Bandwidth is decimal GB/s before OS and workload limits.

True CAS Latency

10.00

ns from CL and MT/s

Row Miss Read

22.67

tRCD + CL + overhead

Usable Bandwidth

84.48

GB/s after efficiency

Row Cycle Time

44.67

tRAS + tRP in ns

Full Timing and Bandwidth Breakdown

🧮Memory Spec Grid

0.333

Clock Period ns

Total GB

96.0

Peak GB/s

Latency Grade

📊DDR5 Preset Timing Table

Named Kit	Rate	Primary Timings	CAS ns	Best Fit
JEDEC DDR5-4800 CL40	4800 MT/s	40-40-40-77	16.67 ns	Safe boot, OEM systems
Creator DDR5-5600 CL36	5600 MT/s	36-36-36-89	12.86 ns	Content PCs and NAS builds
AM5 Sweet Spot 6000 CL30	6000 MT/s	30-38-38-96	10.00 ns	Balanced gaming and home lab
Balanced DDR5-6400 CL32	6400 MT/s	32-39-39-102	10.00 ns	Fast desktop tuning
OC DDR5-7200 CL34	7200 MT/s	34-44-44-105	9.44 ns	High bandwidth workloads
Test Bench DDR5-8000 CL38	8000 MT/s	38-48-48-128	9.50 ns	Validated overclock testing

📐Formula Reference Table

Metric	Formula	Example at 6000	Why It Matters
Clock period	2000 / MT/s	0.333 ns	Base tick for DDR timings
True CAS	CL x period	30 x 0.333 = 10.00 ns	Best quick latency comparison
Row miss read	(tRCD + CL) x period	68 x 0.333 = 22.67 ns	Random access to a closed row
Row cycle	(tRAS + tRP) x period	134 x 0.333 = 44.67 ns	Full activate and precharge loop
Peak bandwidth	MT/s x bytes x channels / 1000	96.0 GB/s dual 64-bit	Sequential copy and iGPU ceiling

🖥Channel Bandwidth Table

Configuration	Channels	Width Used	DDR5-6000 Peak	Typical Use
Single DIMM desktop	1	64 bit	48.0 GB/s	Basic office or troubleshooting
Dual-channel desktop	2	64 bit each	96.0 GB/s	Gaming, NAS, home server
4-channel HEDT	4	64 bit each	192.0 GB/s	VM hosts and workstation loads
8-channel server	8	64 bit each	384.0 GB/s	EPYC/Xeon memory-bound services

🔧Practical DDR5 Tuning Table

Scenario	Watch First	Healthy Target	Tradeoff
Game server host	CAS ns and tRCD ns	10-12 ns CAS	Stability beats peak MT/s
VM lab with many guests	Capacity and channels	Dual channel or better	More DIMMs can reduce max rate
iGPU media box	Usable bandwidth	80+ GB/s dual channel	Bandwidth can matter more than CL
ECC workstation	JEDEC timing and uptime	Validated ECC profile	Higher ns but safer operation

💡DDR5 Calculation Tips

Latency tip: CAS cycles alone can mislead. Compare CL multiplied by clock period, because DDR5-6400 CL32 and DDR5-6000 CL30 both land at about 10 ns.

Bandwidth tip: Use the actual populated channel count. Two DDR5 DIMMs on a mainstream desktop usually means dual channel, while one DIMM often cuts bandwidth in half.

When you purchase DDR5 memory, the advertised speed of the DDR5 memory dont always explain how the DDR5 memory will perform. The advertised speed refers to the data rate in relation to a number of millions of data transfers that can occur each second. The performance of the DDR5 memory is instead related to the number of nanoseconds it take for the data to travel from the processor to the DDR5 memory.

A tool that calculates this latency allow for consumers to compare different kits of DDR5 memory and there latencies. The latency calculator requires a few different inputs in order to calculate the latency of the DDR5 memory that youll be purchasing. The first of these values is the CAS latency, which is a visible value on the DDR5 memory products.

How to Compare DDR5 Memory Latency and Speed

However, this value also requires understanding the clock period in which the CAS latency is measured; higher data rates correlate with shorter clock periods. The latency calculator performs these calculations; no math are required from the consumer. Other timings related to the memory controller include the row access timings.

The memory controller requests data from a row that is not currently open in the DDR5 memory; the memory controller must wait for the data to be accessed after the row to column delay and CAS latency are performed. The latency calculator also calculates this additional wait time. This wait time can help people understand the difference in memory between two kits of DDR5 memory with similar CAS latency values.

Another factor in determining the performance of the DDR5 memory is its bandwidth. The user can calculate this data by multiply the data rate by the channel width, the number of channels, and an efficiency percentage. The result will be the amount of data per second that the DDR5 memory can provide once installed on the computer.

The user can adjust the efficiency to calculate the bandwidth for either a gaming or a server task. One additional function of the latency calculator is to calculate the total capacity of the DDR5 memory. You can enter the number of DIMMS and the size of each DIMM into the calculator in order to determine the total capacity of the memory configuration.

This can help to determine whether all of the memory slots on the computer should be filled with DDR5 memory or whether some slots will need to be left empty in order to achieve the highest possible speeds. People often believe that the lower the CAS latency of the DDR5 memory, the better. However, the calculations made by the latency calculator can help people to understand that this isnt necessarily true; a memory with a higher data rate and a slightly higher CAS latency may have lower true latency.

The latency calculator displays the nanosecond value of the latency of the DDR5 memory kits being compared; displaying this value ensures that those comparing memory kits understands the time related performance of the DDR5 memory. Similarly, if a user is manually tuning DDR5 memory, it may be tempting to alter only a few of the timings. However, altering only one timing may help one portion of the system but hurt another portion of the systems performance.

Each of the timings can be viewed in nanoseconds to help with understanding each of the different component of the memory. In addition to those calculations, real systems have additional constraints to performance beyond the capabilities of the latency calculator. For instance, other components like the motherboard traces, the CPU memory controller, and even the power delivery system to the DDR5 memory will limit the potential performance of the DDR5 memory.

However, the latency calculator is still of great benefit to consumers before purchasing DDR5 memory; it can compare the latencies of different memory kits. Furthermore, once a user purchases and installs DDR5 memory into a computer, the actual latency of the memory can be tested in relation to the calculated latency, as well. The goal is not for the DDR5 memory to have the lowest possible value for each of these timings.

However, understanding the relationships between each of the timings will allow for DDR5 memory to be purchased and installed according to the specific task that the computer that purchases the memory will perform. High requirements for data throughput will require different settings to memory timings than tasks that have a high requirement for the memory to have low latency. The latency calculator is one of the best tool for understanding each of these scenario.