What is the lowest to highest order of I/O performance among these storage devices?

DRAM (Dynamic Random-Access Memory) offers the highest I/O performance due to its extremely low latency and high-speed access capabilities.

SCM (Storage Class Memory) follows DRAM, providing high performance but with slightly higher latency than DRAM.

SSDs (Solid State Drives) come next, offering fast access times but slower than SCM and DRAM.

SATA (Serial ATA) drives are the slowest among these options, as they typically use mechanical components (in the case of HDDs) and have lower data transfer rates compared to SSDs.

References: Dell Information Storage and Management V5 documents Dell Technologies Info Hub​(Dell Technologies Info Hub)