Compare Data Transfer Rates

Find your bottlenecks or optimal specs!

Information

This website uses the following conventions:

• Bits are expressed with bit, except in marketing names (e.g. USB 40Gbps).
• A byte is 8 bits, and is expressed with a capital B.
• The prefixes, k, M, G, T, and P represent the multipliers 10³, 10⁶, 10⁹, 10¹², and 10¹⁵ respectively.
• The prefixes, Ki, Mi, Gi, Ti, and Pi represent the multipliers 2¹⁰, 2²⁰, 2³⁰, 2⁴⁰, and 2⁵⁰ respectively. These are only used for amounts of data.

Below, you'll find brief summaries of all the device types available on datarates.net!

DDR SDRAM

Double Data Rate Synchronous Dynamic Random-Access Memory (DDR SDRAM) is the most common type of RAM used in computers. If you're building a PC, you'll want to ensure your RAM is compatible with your motherboard.

As the name implies, DDR memory performs two transfers per clock cycle. However, the number in the standard (e.g. 4000 in DDR5-4000) represents megatransfers per second, meaning the doubling is already factored in. Each transfer moves a specific number of bits, depending on the DDR version. For example, DDR5 transfers 64 bits per transfer, and in the PC designation (e.g. PC5-32000), the transfer rate is expressed in megabytes per second.

Network

When using a wired network, you can usually achieve speeds close to the theoretical maximum. However, on wireless networks, speeds can vary significantly depending on the situation. It's best to measure the actual speed rather than relying on the manufacturer's maximum speed specifications. However, even with wired connections, some bandwidth is used for data framing and overhead introduced by higher-level protocols like TCP. You can adjust the efficiency percentage to better match your specific use case.

PCI Express

PCIe (Peripheral Component Interconnect Express) is primarily used on motherboards to connect peripherals like GPUs or NICs. However, it is also used in M.2 slots (up to 4 lanes) and externally in technologies like USB4 and Thunderbolt.

The maximum speed of a PCIe connection is determined by two factors: The PCIe version and the number of lanes used. The number of lanes may be limited by the physical connection or the hardware's capabilities. While the PCIe interface uses a specific signaling rate (e.g. 16 Gbit/s per lane for PCIe 4.0), the effective data rate is reduced by encoding overhead: For example, PCIe 4.0 uses 128b/130b encoding, meaning only 128 out of every 130 bits carry actual data, resulting in a slightly lower usable bandwidth.

SATA

SATA (Serial AT Attachment), is used for connecting storage devices like SSDs and hard drives. The maximum speed of a SATA connection depends on the revision used. While the SATA interface uses a specific signaling rate (e.g. 6 Gbit/s for SATA III), the effective data rate is reduced by encoding overhead: SATA uses 8b/10b encoding, meaning only 8 out of every 10 bits carry actual data, resulting in a slightly lower usable bandwidth.

Storage

The data transfer rates of storage devices, such as SSDs and hard drives, are often advertised as the manufacturer's maximum speeds. However, the actual performance you experience can vary significantly based on your specific usage patterns. Factors like file size, read/write operations, and the nature of the workload (e.g. random vs. sequential access) can all affect the real-world data transfer rates. Therefore, while the manufacturer's maximum speed gives an idealized figure, the effective speed you experience may be lower depending on how the storage device is used.

USB

USB has gone through several marketing name changes over the years, often leading to confusion about actual data rates. Up to USB4, the advertised rate refers to the binary signaling rate, without accounting for encoding overhead (e.g., 8b/10b or 128b/132b), which lowers the effective data rate. However, USB4 Version 2.0 (Gen 4) introduces PAM-3 signaling with 11b/7t encoding, where the signaling rate is actually lower at 25.6 GBaud per lane. Additionally, different devices might use different lane configurations, meaning the speeds indicated here represent the maximum possible symmetric rates.

Custom Devices

In case a device type you want to compare is not available, you can use the Custom Device type to select an arbitrary speed.