According to a forecast compiled by market research company Statista, there will be more SSDs sold than HDDs by 2021. This year less than 400 million HDDs will be shipped. By 2021 this number will decline to 330 million HDDs shipped annually, while SSD shipments go up from about 200 million SSDs shipped this year to 360 million by 2021.
Although currently HDDs generally offer greater capacity, a lower price per GB, and a longer product lifetime, SSDs are faster and consume less power.
The decline in shipments of HDDs has been going on since 2015, when 470 million units were shipped. A year later that number dropped to 425 million. At the same time, the number of SSDs shipped in 2015 was 105 million units, which should be more than tripled by 2021 when it's expected that 360 million SSDs are shipped worldwide.
While SSDs are still far more expensive per GB than HDDs, technology advancements caused the price per GB to drop significantly already. Besides the price, SSDs are also available in smaller form-factors which makes it possible to have the same memory capacity in a much smaller space.
Also the speed of SSDs has increased throughout the years, especially thanks to the introduction of NVMe, which removed the SATA bottleneck of about 550 MB/s. This makes SSDs interesting for the ever growing server market.
The price difference between SSDs and HDDs is however still enormous, Amazon sells a WD 4TB HDD for about $109.95, while a Samsung 4TB SSD goes at $1,517.
