With every computer getting faster and faster standard Hard Disk Drives couldn't keep up so SSDs have entered the market providing much better speeds and better responsiveness. By upgrading to an SSD you can bring a breath of fresh air into any system, letting programs load faster and the operating system be more responsive. Even is you're looking to silence your system SSDs are a great step as they don't make any noise due lack of moving parts.
More recently SSDs have apeared in NVMe (Non-Volatile Memory Express) format which is a successor to most common SSD's. It was designed from ground up for SSD storage and performance.
Unlike most SSDs NVMe offer significant lower latency and better performance by connecting directly to the PCIe lanes of your system, helping to to get the best performance from your system. Most NVMe SSD's can be up to 5 times as fast as standard SATA SSD while being more power efficient.
In power limited devices you can also find mSATA is a SSD (Solid State Drive). It's small form factor made it popular in laptops and tablets. Just like SATA-III it sports bandwidth of 6Gb/s giving it plenty of performance for the most demanding tasks.