Gigabyte per second to Kibibyte per second

CPUs constantly shuttle data between RAM and their caches. DDR5-6000 provides about 96 GB/s of bandwidth in dual-channel mode. In games, insufficient RAM bandwidth causes frame drops during complex scenes. In productivity tasks like video encoding, it directly limits how fast the CPU can process data.

Thunderbolt 4 runs at 40 Gbps, which is 5 GB/s. Thunderbolt 5, released in 2024, doubles this to 80 Gbps (10 GB/s) with a burst mode up to 120 Gbps (15 GB/s). This is fast enough to run an external NVMe SSD at near-internal speeds.

Both, depending on generation. A PCIe 3.0 ×4 interface caps at ~3.5 GB/s, bottlenecking modern NAND. PCIe 4.0 ×4 raises this to ~7 GB/s, and PCIe 5.0 ×4 to ~14 GB/s. The drive's NAND flash and controller also have limits — the fastest SSDs and the fastest interfaces are in a constant leapfrog.

GPUs use wide memory buses (256–384 bits) with very fast HBM or GDDR6X memory running at high clock speeds. An RTX 4090 has a 384-bit bus with GDDR6X at 21 Gbps per pin, totalling 1,008 GB/s. HBM3 in data center GPUs achieves 3,000+ GB/s through stacked memory with 4096-bit buses.

At multi-GB/s rates, CPU processing speed, software efficiency, and thermal throttling become bottlenecks. A 14 GB/s PCIe 5.0 SSD can deliver data faster than most applications can consume it. Decompression, parsing, and memory allocation in software often cannot keep up with raw storage bandwidth.

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.