Flash Memory vs. HDD: Can Flash Replace Hard Drives?

The most significant difference between traditional mechanical hard disk drives (HDDs) and flash memory is speed. Flash memory is much faster because it uses a solid-state memory chip with no moving parts. Hard drives use disk platters with a magnetic coating that takes a magnetic imprint of the data saved onto the platters—as the disk platter spins, a read-and-write head either retrieves data from the spinning platter or writes data to the platter. 

But is faster always better, and are there still use cases for which HDDs are more well-suited than flash? We compared flash and HDDs to see if the faster new technology can completely replace the older one, or if both still earn their keep.  At a high level we found that flash is best for working with high-resolution images produced by applications similar to computer-aided design, geographic information systems, or video editing software, while HDDs are best for meeting mass storage requirements when data must be stored for several years and does not need to be accessed very often. This article compares the two in more detail.

Flash Memory vs. HDD at a Glance

Learn more: Flash Storage vs. SSD: What’s the Difference

Best for Pricing: Tie

• Solid state drives (SSDs), which use flash instead of moving parts, are more expensive than HDDs, though their reliability might justify the cost depending upon how they will be used. HDDs are recommended for a typical business or home use with simple processing needs, like MS Office or Google Suite products, or  if budget is a concern. 
• High-intensity processing applications, like Adobe Creative Suite, for example, or generating high quality graphics or multimedia for clients are better suited for solid-state flash drives.

Best for Backups and Archiving: HDDs

• Backing up or archiving data where it does not need to be accessed regularly or repeatedly can be done on hard disk drives for a fraction of the cost of solid state drives. 
• Enterprise applications like customer relationship management (CRM) and enterprise resource planning (ERP) software can usually be supported with HDDs.

Best for Data Retrieval: Flash

• Solid-state hard drives are better-suited to applications and use cases requiring fast data retrieval, or the quick and efficient movement of large data files.

Best for Durability and Reliability: Flash

• With their wear-leveling features and no moving parts, SSDs can withstand drops, shakes, and shocks, giving them a clear advantage on the durability of hard drives. 
• They’re also more reliable over time, as they cannot break down mechanically.

Who Shouldn’t Use Flash?

In most cases, flash solid state drives are better performers with increased durability and reliability, but not everyone needs those benefits.

• Those using older computers may find them incompatible with flash SSDs, as older motherboards lack the serial ATA (SATA) interface connection.
• Those on limited budgets or who don’t need to quickly and regularly retrieve or work with data can save on cost—especially in arrays or network attached storage (NAS) devices with multiple drives—by sticking with more affordable hard disk drives.

Learn more: What is Flash? NAND vs. NOR

Who Shouldn’t Use HDDs?

Business professionals and content creators need the faster responsiveness and the durability of solid state drives and should avoid HDDs.

•  When quicker file access, rapid application acceleration, and quicker boot-up times are needed, HDD performance eliminates itself based on its efficiency metrics.
• Computer-intensive applications that perform complex computations, simulations, or data-intensive processing need solid-state drives.

Bottom Line: Flash vs. HDD

While their cost has come down, solid state drives using flash remain more expensive than HDDs. Data centers or server arrays using multiple drives to backup and archive data that won’t be accessed frequently might still opt for the affordability of HDDs, as might businesses looking to outfit computers for a number of employees that have minimal processing demands—those using only productivity software, for example. But on nearly every performance metric, flash-based solid state drives outperform traditional mechanical hard disk drives.

Read next: Is the Hard Disk Drive Obsolete?