SSDs (solid-state drives) offer extremely reliable, fast, and consistent performance over many, many years. They aren’t subject to problems that can harm even the best-designed modern hard disk drives (HDDs): exposure to magnetic fields or the failure of moving parts inside the drives.
But SSDs remain expensive many years after they first appeared. Nearly all other aspects of computation—from processors to RAM to LCD displays—have dropped dramatically in price while improving in quality and performance year after and year. SSDs initially followed that curve, especially for lower-capacity drives, but tapered way off. The cost of manufacturing higher-capacity memory chips used in SSDs hasn’t dropped much in recent years.
That means a 1TB SSD for a laptop can still cost $300 to $400, while a similar HDD can be bought for under $100. In the case of Apple, with its high markups on memory and drives, it’s an extra $700 to the cost of a current iMac if you want to equip it with 1TB SSD.
Read more at MacWorld.com