Mainframes vs. Servers: How They Are Different (and Similar)

Mainframes and servers

Mainframes vs. servers–if you’re expecting a magic bullet explanation of how they differ, you’re in for a surprise. They look about the same, they have the same sort of technology, but where they differ is in scale. 

Trying to compare mainframes to servers is like asking what’s the difference between an apple and a bushel of apples. Or ants and GodzillaWho said we IT types aren’t creative. 

Both can perform the same sort of tasks, but the big difference is how many and how fast they can accomplish those tasks. A mainframe can be a server, or a bunch of servers can act as a mainframe. It really depends on how they’re being utilized.

If you manage and maintain mainframes every day, this article’s not for you. You already know the difference, and do you even care, so long as the next batch of transactions goes through in the next 0.005 of a second? But it can make for some lively pub talk. 

👍🏻 Here’s the colloquial distinction of mainframes vs. servers you’re looking for.

Mainframes are highly specialized hardware designed to perform specific tasks as fast and as efficiently as possible. They cost millions and can perform billions of transactions every day.

Servers can be specialized, too, but aren’t considered as powerful as mainframes, able to do millions of transactions every day.In the stratospheric world of enterprise data centers, the lines between mainframes and servers are blurred, and increasingly the biggest difference between them is what you call them rather than outright functionality.

What Is a Mainframe?

The term mainframerefers to a category of computers designed to process a vast number of transactions and accept and support thousands of user requests, all while performing reliably. Mainframes utilize scalable software and are optimized for executing billions of transactions per day.

They are used for a wide range of functions, including:

  • Managing mission-critical ERP operations across the enterprise. 
  • Handling billions of transactions every day at banks and financial institutions 
  • Securing credit card payments
  • Encrypting mobile interactions in real-time
  • Providing real-time insights on transactions being performed

71% of the Fortune 500 uses mainframes today, and the vast majority of those are IBM Z mainframes (not running on the x86 or ARM architectures you’ll find in consumer and even commercial servers).

There was a time when mainframes were something the size of a large building (and got the moniker ‘Big Iron’, as a result), but that’s no longer the case, as microchips have shrunk and processing power can be packed in more densely.

What Is a Server?

With Goliath out the way, let’s consider David. Servers are a class of computers that are used to serve clients data and services. Servers can be optimized for the tasks they’re expected to perform, such as acting as file servers, commercial databases servers, application servers, and web servers.

Servers typically cost less than mainframes, though commercial-grade server hardware easily runs into the hundreds of thousands of dollars. 

Servers can perform the same tasks as mainframes (and vice versa), but they are not going to be as fast or efficient at them. You will likely need a larger server farm to accomplish the same tasks that a single mainframe can. (More on that in a bit).

Mainframes vs. Servers: Here’s Where the Differences End

More gigahertz, more memory, more computer power than your server–no, that’s not an ad for a consumer product, that’s how IBM markets enterprise mainframes. Enterprises are looking, albeit at a different scale, for the same thing–to be able to perform more tasks, faster, and more efficiently.

Mainframes and servers don’t exist in isolation, and any infrastructure utilizing a mainframe will rely on servers to handle other workloads. IBM says so itself, “a server, with the mainframe simply being the largest type of server in use today,” and that mainframes are used in conjunction with smaller server networks.

The server vs. mainframe distinction is, to an extent, a hangover of the past. Differences in hardware architectures (IBM Z systems vs. x86/ARM), operating systems (z/OS vs. Linux), and the expertise required to operate them means you can’t migrate workloads between them.


Some Key Differences Between Mainframes and Servers

With that in context, let’s explore some of the differences between mainframes and servers.



Mainframes are widely used for high-volume, compute-heavy workloads, such as OLTP applications, batch processing, and ERP. They form the backbone of the global economy, being used at financial institutions which must process large volumes of transactions and crunch application requests in real-time. 

Consistency and integrity are vitally important, which is why mainframe applications are designed to ensure a high level of transaction integrity. When you’re handling terabytes of data every day and billions of transactions, reliability counts.


Servers are optimized more for delivering a service to clients rather than transaction processing and performing complex computations. They perform tasks such as file hosting, hosting cloud-based applications, DNS hosting, VPNs, and networking. Servers can be deployed in arrays to share the workload.


Differences Between Mainframes and Servers



There are architectural differences between mainframes and servers which gives them their unique identity (though, today, that’s as much a function of marketing). 

Mainframes are often branded as such, and they’re expected to operate on systems from companies like IBM and Broadcom. Applications and programming languages are different, too, with mainframes running Db2, CICS, REXX, and COBOL applications. 


Servers come in all shapes, sizes, and capabilities, testament to the wide range of uses they are put to. They tend to run on x86 or ARM processors and use operating systems built on Linux or Microsoft WIndows. That said, specialized servers may very well use proprietary software and hardware.

3.Load Factor


Mainframes are designed to deliver consistent, reliable performance even at high utilization over prolonged periods of time. Greater redundancies are built into mainframe systems to minimize the risk of catastrophic failure, and single points of failure are avoided to prevent service interruptions.


If certain server components are overloaded with tasks, the overall performance of the server can be impacted. It’s why organizations maintain additional servers for overflow capacity and to better share workloads between systems. 

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Mainframe components are connected to each other through high-speed communications channels that combine low latency, high bandwidth, and integrity. Input and output operations are managed by separate sub-systems to maximize mainframe performance for high-value workloads.


Servers are typically connected to the networking infrastructure of the organization, meaning data transfer isn’t as optimized. Separate networking systems can introduce latency into operations, too.

Mainframes vs. Servers: Making the Most of Your Technology


Mainframe vs. Servers

Both are incredibly complex pieces of technology, and it takes a qualified team to maximize their utility. That’s why 60% of the Fortune 500 and government agencies across North America turn to us to upskill IT teams and keep competencies current. 

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About Author Michael Friedlander

I have devoted my entire 45 year career working with all aspects of mainframe and mainframe technology in both public and private sectors. 


Published August 17, 2022