DRAM SSDs vs. DRAM

Solid-state hard drives (SSDs) come in various form factors and a wide range of capacities, but another way to differentiate among them is whether or not a drive has Dynamic Random Access Memory, or DRAM. DRAM is a widely used memory chip that can hold large amounts of data but requires a lot of power. SSDs with DRAM are better for graphic-intensive applications like Adobe Photoshop, AutoCAD, CorelDraw, or video editing software. SSDs without DRAM are slower and less expensive, which makes them sufficient for budget-conscious individual users whose computer use is limited to productivity software and web browsing. But they’re still faster than mechanical hard drives, making DRAM-less SSDs well-suited for use in enterprise hyperscale data centers that deploy software over several thousand servers.

This guide provides a more detailed look at the advantages and disadvantages of each type of SSD to help buyers decide which is better for their needs.

SSDs work more like large USB drives than traditional mechanical hard disk drives, storing data on a number of flash memory cells. That data is frequently moved around the cells to keep them from wearing out due to repeated read or write requests. To track the data, the drive needs to map it so that it knows exactly where to look when you need it.

Some SSDs store that map on the DRAM. DRAM-less SSDs store it in the flash cells, which are slower. The constant use also takes a toll on the flash, resulting in a shorter life span. Without DRAM, vendors are also able to manufacture and sell SSDs for less, making them more affordable than their faster counterparts.

While SSDs with DRAM may seem like the better fit for most use cases, both types have their place depending on how they will be used. Here are a few ways to think about which type is better for a specific need.

Depending on overall capacity, DRAM-less SSDs cost less than SSDs with DRAM. A June 2023 survey of prices revealed a differential of from $15-35. Budget-conscious users without high-intensity data needs may find DRAM-less SSDs sufficient to add speed to a new computer or to give a boost to an older one.

Though SSDs with DRAM are faster by design, the actual speed difference is minimal, and both are still faster than traditional mechanical HDDs. Test results from one manufacturer showed read/write speeds of 560/510 MB per second for its SSDs with DRAM and 550/500 MB per second for those without. While speeds may vary, most users will not notice a difference in the performance of either SSD in a computer used mostly for productivity software and web browsing.

Unlike flash memory, DRAM requires constant power to function, which means DRAM-less SSDs use less power than their counterparts. In a laptop, this means DRAM-less SSDs can improve battery life.

It can also lower the cost of power consumption. For single-machine users, the difference here is probably negligible, but in arrays of multiple SSDs the cost of power can add up.

SSDs with DRAM use wear-leveling—a process programmed into flash devices that maximizes efficient usage of the memory blocks—that prolongs the life of the device by minimizing wear and tear from constant usage by applying the Program and Erase (P/E) cycles evenly across all blocks. (A typical block can withstand about 100,000 P/E cycles.) Without wear-leveling, DRAM-less SSDs risk overusing blocks that can shorten the lifespan of the drive.

In a hyperscale data center—massive data centers that can support thousands of individual servers connected via high-speed internet—SSDs with DRAM can interfere with essential host server operations and degrade performance. Each server's host memory buffer (HMB) uses server DRAM that can schedule and perform similar actions to SSD DRAM without interfering with the host application's overall operations. Though the HMB does not work as well as the DRAM in SSDs, using it extends the longevity of the server SSDs, making DRAM-less SSDs the superior choice for this use case.

While both SSDs with DRAM and DRAM-less SSDs have their place and provide varying degrees of performance, longevity, and reliability, there are certain cases when one is clearly preferable to the other.

Enterprise organizations building out hyperscale data centers should not use DRAM SSDs. The risk of DRAM interference could affect the overall system performance and have a negative impact on business applications across multiple servers.

Smaller or budget-conscious organizations purchasing SSDs in volume—for example, a school district or SMB outfitting schools or offices with computers that won't be used for graphics-intensive applications—would benefit from the lower cost of SSDs without DRAM.

Users or businesses that require high-end applications to generate digital products from video or photo editing, AutoCAD, or graphic design software should not use DRAM-less SSDs and should instead seek out SSDs better suited for high-intensity computing.

There are alternatives to SSDs beyond traditional mechanical hard disk drives, including nonvolatile memory express (NVMe) and solid state hybrid drives (SSHDs).

NVMe is a new storage access and transport protocol for flash and next-generation SSDs that accesses flash storage using a Peripheral Component Interconnect Express (PCIe) bus more quickly than HDDs and traditional flash architectures. NVMe storage is already used in business environments where microseconds count and real-time customer interaction is critical. It's also used in business Artificial Intelligence (AI) software.

Solid state hybrid drives take the best features from both HDDs and SSDs. Like HDDs, hybrid drives have a spinning disk and actuator arm that writes data on it, and an attached solid state drive. Data can be written on either the mechanical hard disk or the SSD. The choice is dictated by user habits—infrequently used data is stored on the traditional hard drive and frequently used data is stored on the solid-state hard drive.