Thick vs. Thin vs. Zero Clients: Which Model Is Right for You?

For years, organizations have been searching for a “one-size-fits-all” approach to computing, says Andrew Hewitt, an analyst for end-user computing with Forrester.

First, every user had a desktop computer. Then, it seemed as though virtual desktop infrastructure (VDI), paired with thin clients, might completely replace “thick” PCs inside the enterprise. After that, some observers thought that tablets might kill off both thick clients and VDI, unifying end-user computing in a sleek, mobile form factor that mostly relied on cloud- or server-hosted apps. 

“All of these things that were promised never really happened,” Hewitt says. “What happened is the proliferation of all these different devices that match with different use cases.” 

This proliferation has led to a scenario in which, instead of simply rolling out the same device types for all users, organizations must carefully consider which user roles are best suited to different form factors and operating systems. Broadly speaking, devices can be divided into three categories: thick clients, thin clients and zero clients. Each category has its own advantages and drawbacks, and organizations risk missing out on efficiencies and cost savings if they go the wrong route. 

“There might be a certain portion of users where thin clients make sense, and there might be another portion where thick clients make more sense,” says Brian Madden, lead field technologist for VMware. “Everyone these days is mixing and matching.” 

Not every device can neatly be lumped into a single slot. For instance, some might argue that an Apple iPad is a thick client because of its robust operating system, while others would call it a thin client due to the fact that because it is largely used to connect to cloud apps. 

However, the industry generally follows these definitions:

Thick clients: Also called “rich” clients (or even “fat” clients), these are typically traditional PCs such as desktops and laptops, which provide a high level of functionality independent of a central server. These machines usually provide better multimedia performance than thin and zero clients, and also allow users to work offline. “When I think about a rich client, it’s a general-purpose device,” says Roger Cao, senior principal technical program manager for Citrix. “It’s almost like a Swiss Army knife. You can approach the unknown, and know that you have the right tool.” 

Thin clients: In a thin client model, applications are run and data is stored on a central server rather than on the device itself. While many people use the term “thin client” to refer to particular device types such as smartphones, tablets or stripped-down desktops, Gartner notes that many organizations also use a thin client model with traditional PCs. “In fact,” Gartner states, “more than 85 percent of devices used to display thin-client Windows applications are regular PCs, typically configured with both ‘fat-client’ applications and access to thin-client ones.” Cao notes that thin clients are often used with purpose-built, industry-specific applications. “You often hear about them running line-of-business applications in sectors like retail and manufacturing,” he says. 

Zero clients: These are also called “ultra thin” clients. Like thin clients, zero clients connect to on-premises servers or public cloud resources to access data and applications. However, this model goes a step further, as zero clients feature no local storage. While a thin client typically has its own operating system and stores configuration settings in flash memory, a zero client lacks even these bare minimum features. Rather, a zero client merely acts as a terminal for delivering applications and data to end users.

In a 2019 report titled “The Future of Enterprise Computing,” Forrester predicts that organizations will increasingly adopt an “80/20 split” — with 80 percent of computing tasks being completed on lighter devices such as smartphones, foldable displays, voice speakers and smart glasses. 

Among Forrester’s predictions:

• Although the bulk of tasks will be completed on lighter devices, heavy devices will remain “crucial,” especially for engineers, designers and data scientists. 
• The variety of device form factors will continue to expand in size and diversity, ranging from “nearly invisible to extremely tangible.” 
• Artificial intelligence will become an “intermediary” between machines and employees, delivering real-time insights into customers and business operations in ways that drive fewer typing-based interactions. 
• The need for highly mobile, hands-free solutions will drive investments in wearable devices to support workers such as nurses, retail associates and field technicians.
• Users will rely less on full-blown mobile apps to get work done, and will instead utilize microapps that deliver a “slice” of the functionality of larger, back-end applications. Workers will also rely more on web-based applications for faster boot time and accessibility outside of traditional app stores.

As clients get thinner, they tend to also become more secure, easier to manage and less costly — and often last longer, too. However, thicker clients provide more functionality, and are necessary to support some users, especially those who frequently work outside of the office and need to be productive even when they lack Internet access or a direct connection to the enterprise network. 

The key, experts say, isn’t to lock into one model or another across the enterprise, but rather to adopt the right client type for any given use case. 

“It comes down to your application delivery method,” says Madden. “For example, if you have embraced remote desktops, whether that’s VDI or a terminal server desktop, and users typically sit at a desk, then thin clients are perfect for them.” Madden gives the examples of call centers, trading floors and nursing stations as good fits for thin clients. 

Cao notes that mobile workspace solutions from vendors such as Citrix enable workers to use thin clients for a wider range of tasks than in the past. However, he notes that thick clients are still needed for more processing-intensive use cases, such as when employees need to work on multiple high-resolution displays. Cao recommends that organizations consider the total cost of ownership for different client types, and notes that thick clients may require more hands-on management on the part ofby IT staff. “When you think about these different devices, I would go beyond the price point and take a look at the efficiency and productivity that the devices offer,” he says. 

At its essence, Hewitt says, the decision about which client type to utilize is really a choice between maximum functionality and ease of management. “There’s that central tension between giving employees the freedom to work in whatever way they want, and then keeping the organization secure and reducing the management overhead,” Hewitt says. “A lot of organizations are trying to figure out how to achieve both. It’s a hard balance to strike.”