The primary difference between SSDs (solid-state drives) and HDDs (hard disk drives) lies in their technology and performance. SSDs utilize flash memory to store data, resulting in significantly faster read and write speeds compared to HDDs, which rely on spinning magnetic disks. This speed advantage translates to quicker boot times, faster application loading, and improved overall system performance. Additionally, SSDs are generally more durable, consuming less power and producing less heat, making them ideal for modern computers and portable devices, whereas HDDs are often more cost-effective for larger storage capacities.