Numbers To Know hard
What is the approximate bandwidth of a full PCIe 4.0 x16 slot (e.g., used by GPUs or high-end NVMe RAID)?
- A 10 GB/s
- B 32 GB/s
- C 64 GB/s
- D 1 TB/s
Answer: C. 64 GB/s
PCIe (Peripheral Component Interconnect Express) is the high-speed bus that connects components like GPUs and NVMe drives to the CPU. PCIe 4.0 delivers about 2 GB/s per 'lane'. A full-sized x16 slot therefore provides 32 GB/s of bandwidth in each direction, for a total aggregate throughput of 64 GB/s. As AI workloads increase, even this massive speed is becoming a bottleneck, which is why PCIe 5.0 (which doubles this again to 128 GB/s) and specialized interconnects like NVLink are becoming essential for modern high-performance computing centers.
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