Gigabyte per second to Gibibyte 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.

GPU memory is addressed in binary (power-of-2 bus widths like 256-bit or 384-bit), so binary units naturally describe the actual hardware capability. Some vendors use GiB/s to be precise, while marketing materials prefer the larger-sounding GB/s number. The RTX 4090's 1,008 GiB/s is 1,082 GB/s — the latter sounds faster.

DDR5-6000 in dual-channel mode provides about 93 GiB/s (100 GB/s). Quad-channel DDR5 on workstation platforms doubles this to ~186 GiB/s. The actual usable bandwidth depends on memory access patterns — random access achieves far less than sequential streaming.

Memory bandwidth (50–100+ GiB/s for DDR5) measures how fast the CPU can read/write RAM. Storage bandwidth (3–14 GiB/s for NVMe SSDs) measures persistent data transfer. Memory is 10–30× faster because DRAM has nanosecond latency while NAND flash has microsecond latency. They serve different roles in the data hierarchy.

Yes. For memory bandwidth, run a STREAM benchmark (available for Linux and Windows). For storage, use fio or CrystalDiskMark. GPU memory bandwidth can be tested with gpu-burn or vendor-provided tools. All will report in either GiB/s or GB/s depending on the tool — check which one.

Electrical signalling on copper traces maxes out around 112 Gbps (about 13 GiB/s) per lane with current technology. Beyond that, optics take over — silicon photonics interconnects can push individual channels to 200+ Gbps. The physical speed of light in fiber is not the limit; it is the modulation and detection electronics.