Mebibyte per second to Megabit per second

dd uses binary units because Linux filesystems work in binary block sizes (4 KiB, etc.). Drive manufacturers use decimal MB/s because it makes speeds look about 5% higher and aligns with their decimal capacity marketing. A "550 MB/s" SSD shows roughly 524 MiB/s in dd.

Run "dd if=/dev/zero of=testfile bs=1M count=1024 oflag=direct" and it will report write speed in MiB/s. For read speed, use "dd if=testfile of=/dev/null bs=1M". The oflag=direct flag bypasses filesystem cache to measure actual disk performance.

No — 550 MiB/s is about 577 MB/s, and 550 MB/s is about 524 MiB/s. The ~5% difference means an SSD advertised at 550 MB/s will show around 524 MiB/s in Linux tools. It is not a defect or false advertising, just different unit systems measuring the same physical speed.

A RAID 0 stripe of two SATA SSDs gives roughly 1,000–1,100 MiB/s sequential reads. Four NVMe SSDs in RAID 0 can hit 12,000–14,000 MiB/s. RAID 5/6 arrays sacrifice some write speed for redundancy — expect 70–90% of raw stripe performance on writes.

Sequential reads let the drive stream data from contiguous locations, maximising throughput. Random I/O forces the controller to seek different addresses, adding latency per operation. An NVMe SSD might do 7,000 MiB/s sequential but only 50–80 MiB/s random (at 4 KiB block size), because the bottleneck shifts from bandwidth to IOPS.

Because ISPs advertise in megabits (Mb) while download managers show megabytes (MB). There are 8 bits in a byte, so 100 Mbps ÷ 8 = 12.5 MB/s. Your connection is working perfectly — it is just a unit mismatch that has confused people for decades.

Netflix recommends 25 Mbps for 4K, YouTube suggests 20 Mbps, and Apple TV+ needs about 25 Mbps. In practice, 50 Mbps gives comfortable headroom for one 4K stream plus normal browsing. A household streaming on multiple devices simultaneously should aim for 100+ Mbps.

Wi-Fi shares bandwidth among all connected devices, loses throughput to interference from walls and other electronics, and uses half-duplex communication (it cannot send and receive simultaneously). A 300 Mbps Wi-Fi router might deliver 100–150 Mbps to a single device in practice, while Ethernet gives you the full rated speed.

Download Mbps measures data coming to you (streaming, browsing), while upload Mbps measures data you send (video calls, cloud backups). Most home connections are asymmetric — 100 Mbps down but only 10–20 Mbps up. Fiber-to-the-home plans increasingly offer symmetric speeds.

Surprisingly little — most online games use only 1–3 Mbps of bandwidth. What gamers actually need is low latency (ping), not high throughput. A 10 Mbps connection with 15ms ping will outperform a 500 Mbps connection with 100ms ping for gaming every time.