Kibibyte per second to Gibibit per second

Rsync follows IEC binary conventions because it deals with file sizes that are measured in binary units by the filesystem. Since files occupy whole filesystem blocks (typically 4 KiB), reporting transfer speed in KiB/s makes the math consistent with actual data moved on disk.

1 KiB/s (1,024 bytes/second) is 2.4% faster than 1 kB/s (1,000 bytes/second). The difference is tiny at this scale but matters when you are designing buffer sizes for embedded systems where every byte of RAM counts.

Microsoft started using binary units more consistently in Windows 10 after years of ambiguity where "KB" sometimes meant 1,000 and sometimes 1,024 bytes. The shift toward KiB follows IEC recommendations and reduces confusion, though the transition is still incomplete across all Windows tools.

A 3.5-inch floppy drive transferred data at about 31–62 KiB/s (250–500 kbps). Copying a full 1.44 MB floppy took roughly 25–50 seconds. For comparison, a modern NVMe SSD is about 100,000 times faster.

In embedded systems with tight memory constraints, confusing 1,024 with 1,000 can overflow a buffer. In network protocols, a spec written in KiB/s being implemented as kB/s means transmitting 2.4% less data than expected per second — enough to cause timing violations in real-time systems.

At gibibit speeds, 7.4% represents a substantial amount of data. The difference between 10 Gibps and 10 Gbps is 737 Mbps — enough bandwidth for several 4K video streams. When designing storage fabrics or HPC interconnects, misinterpreting the unit can lead to underprovisioned systems.

PCIe specifications are actually defined in GT/s (gigatransfers per second) with specific encoding overhead. PCIe 3.0 uses 128b/130b encoding at 8 GT/s, giving about 985 MB/s per lane — which is closer to binary GiB/s than decimal GB/s. The industry uses both units somewhat loosely.

InfiniBand specifications use decimal rates (HDR = 200 Gbps, NDR = 400 Gbps per port). However, some HPC benchmarks and documentation convert to binary units for consistency with memory bandwidth figures. Always check the document's unit convention to avoid the 7% discrepancy.

Ordering a 100 Gibps fabric when you needed 100 Gbps means overpaying for 7.4% more bandwidth than necessary. Conversely, provisioning 100 Gbps when your workload needs 100 Gibps leaves you 7.4% short, potentially causing congestion during peak loads. At data center scale, these margins translate to real money.

Unlikely. Networking is firmly decimal (Ethernet, fiber optics), while memory and storage have binary roots. The two worlds overlap in storage networking, causing permanent confusion. The best practice is to always explicitly state "decimal" or "binary" in specifications rather than hoping everyone agrees.