On Sunday, 19 January 2020 3:47:00 PM AEDT Craig Sanders via luv-main wrote:
NVME SSDs are **much** faster then SATA SSDs. SATA 3 is 6 Gbps (600 MBps), so taking protocol overhead into account SATA drives max out at around 550 MBps.
NVME drives run at **up to** PCI-e bus speeds - with 4 lanes, that's a little under 40 Gbps for PCIe v3 (approx 4000 MBps minus protocol overhead), double that for PCIe v4. That's the theoretical maximum speed, anyway. In practice, most NVME SSDs run quite a bit slower than that, about 2 GBps - that's still almost 4 times as fast as a SATA SSD.
Some brands and models (e.g. those from samsung and crucial) run at around 3200 to 3500 MBps, but they cost more (e.g. a 1TB Samsung 970 EVO PLUS (MZ-V7S1T0BW) costs around $300, while the 1TB Kingston A2000 (SA2000M8/1000G) costs around $160 but is only around 1800 MBps).
Until recently I had a work Thinkpad with NVMe. That could sustain almost 5GB/s until the CPU overheated and throttled it (there was an ACPI bug that caused it to falsely regard 60C as a thermal throttle point instead of 80C). But when it came to random writes the speed was much lower, particularly with sustained writes. Things like upgrading a Linux distribution in a VM image causes sustained write rates to go well below 1GB/s. The NVMe interface is good, but having a CPU and storage that can sustain it is another issue. -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/