Why Are PC Cases So Big? Reasons, Features, And Benefits

One of the first things you’ll most likely notice about your computer is its form factor. While there has been a notable focus in the past on designing cases that maintain a small footprint in your space, PC cases seem to be getting bigger. But why are some PC cases so big now?

Some PC cases are so big mainly to accommodate the motherboard’s form factor. Big PC cases allow ample airflow and breathing room for better cooling, support additional customization and provide room for upgrades all while making your computer easier to work on.

In this article, I’ll share the various factors impacting case size to explain why some PC cases are as big as they are.

I’ll also discuss how the size of the case affects critical aspects of your PC, such as performance, cooling capability, and hardware upgrades. Let’s get started. 

a large tower computer case

Factors affecting PC case size

PC cases come in varying shapes and sizes. According to Jerome Casey of Technological University Dublin, the size and shape of the PC case depend on the motherboard’s form factor. 

This is because the motherboard is the largest portion of most PCs. Computers with more prominent cases tend to be common in business environments because they allow greater RAM, processing power, and GPU upgrades. 

These larger computers also feature more expansion slots and greater room for driver bays, allowing larger storage capacities without compromising cooling efficiency. 

To get a better understanding of the factors that affect PC case size, let us first outline the major PC components and how they affect the size of the case: 

  • The motherboard.
  • The power supply unit.
  • Drive bays and expansion slots.
  • Cooling fans.
  • Cable management.

These are discussed further below.

The motherboard

a motherboard for a desktop computer

The motherboard holds the major processing parts of a computer. Accordingly, its shape and design will greatly impact the size and shape of the case. 

This is mainly because the motherboard’s shape and size affect each critical component’s position.

The motherboard also has several critical components which attach to it, including the CPU, RAM, audio components, video components, expansion cards, and networking hardware. 

Because some modern PCs have larger motherboards, they tend to have much bigger cases. 

The power supply unit (PSU)

a desktop computers power supply

The power supply unit converts AC into DC, which powers your computer. According to Jerome Casey, the form factor of a PC’s power supply needs to match that of the case and the motherboard it’s meant to power. 

Although most PCs are fitted with standard ATX power supplies of the same form factor, Intel explains that these power units differ in size and are designed to fit specific cases. 

PC World reiterates the above position, noting that some computers use larger and heavier power supply units, and these differences will likely be reflected in the case size.

These larger power supply units are also fitted with larger heatsinks and bigger cooling fans, which means they take on greater size.

Therefore, some PC cases are large because they are designed to fit larger power supply units or to allow the upgrade to a larger power supply unit in the future

Drive bays and expansion slots

empty drive bay slots inside a desktop computer case

Drive bays and expansion slots provide room for upgrades. Computers with multiple expansion slots and drive bays take on a larger size. 

Most modern PCs are designed with a high degree of versatility in mind, making it easy to upgrade various components for accelerated performance.

Because of this allowance for expansion, these PCs have more drives and slots than standard models. Ultimately, this means they’ll have a larger case when compared to these standard computers. 

PC cases also differ in size depending on the number of supported drives for the specific case.

Therefore, some cases are larger simply by virtue of having a larger number of supported drives.

 It’s also important to note that there are three types of drive bays that vary in size. These include: 

  • 5.25-inch (13 cm) drives, typical for optical drives.
  • 3.25-inch bays (8 cm), standard for mechanical drives.
  • 2.5-inch (6 cm) drive bays, typically used for solid-state drives.

Cooling fans

a desktop pc cooling fan

PC cases have built-in vents which let you mount cooling fans to prevent overheating. (The impact of the cooling system on case size will be discussed in detail later in this article.)

Depending on the number, size, and type of fans to be mounted on the PC, some more prominent cases may be used accordingly; Some PCs may have larger cases, while others have much smaller cases. 

Cable management

Different cases feature different approaches to cable management. Some PC cases leave plenty of room towards the back to allow neat cabling.

Depending on the type of cable management option fitted on the case, you may notice some cases appear significantly larger than others. 

How PC case size affects performance

A rocket is shooting through the air indication high speed.

Take a moment to remember how computers were not too long ago. For instance, how do the specs of a computer you bought five years ago compare to your new machine?

A significant feature of contemporary computing is an explosion of computing specs. 

Today, most computers run on powerful CPUs, very high RAM, and monstrous graphics cards.

Additionally, users now enjoy storage capacities that could only be imagined a decade ago.

These components must somehow fit in your computer because if they do not, what good are they to you as the end-user?

Case size affects performance because it offers ample room to fit large CPUs, GPUs, and RAM hardware parts.

More powerful computers have multiple cores, large graphics cards, and more RAM chips installed in the available slots. 

Let’s take a closer look at how these aspects influence performance.

RAM Size and performance

motherboard with extra ram slots compared to a smaller form factor motherboard

RAM stands for Random Access Memory, and it directly impacts your PC’s performance because it speeds up data access and supports fluid multitasking.

Therefore, the more RAM your computer has, the more data it can process at any given time. 

Most modern computers arrive with more than one RAM slot.

While the RAM chips’ physical size has mainly remained the same, the number of RAM slots has increased in modern PCs, with some computers having as many as four slots. 

This necessitates a larger space allowance in the PC’s casing. 

CPU Size and performance

a technician holding up a CPU to camera

The more powerful your CPU, the faster your computer executes tasks and handles resource-intensive performance.

Although, when you have increased processor sizes, the hardware parts will take up more space on your computer. 

In general, more powerful CPUs require more physical space. This is because they use significantly greater power than older computers.

These greater power demands, in turn, necessitate increased capacity in the data center, which often means the PC will take on a more prominent form factor. 

GPU Size and performance

a graphics card assembly 3d modelled parts

Your computer’s GPU also impacts performance.

The size of the GPU is measured in terms of transistor count, and most GPUs, just like CPUs, have gotten significantly larger in terms of physical size. 

The GPU influences performance because more VRAM means your computer can store more data while having faster VRAM enables quicker data transfers.

Like CPU and RAM, modern computers have additional slots to upgrade the GPU, allowing up to four graphics card slots. 

However, by increasing the performance of the GPU, the PC will have a much larger casing than its older counterparts as a consequence. 

The overall impact of case size on performance

Accordingly, the case size influences performance because it determines the size and type of processor, graphics card, and RAM that can be fitted on the computer.

If the case isn’t large enough to accommodate these hardware parts, then something has to give, from a performance standpoint. 

How PC case size affects the cooling capability

the temperature being taken inside a computer using an infrared thermometer

As modern PCs become more powerful on the back of larger CPUs, RAM, and more efficient GPUs, the PC’s design must be optimized to allow cooling. 

The case size affects three key areas that impact cooling, as follows:

  • Fan size and type.
  • Heatsink size and type.
  • Water cooling system.
  • How close components are situated together.

Keep in mind, that as critical performance components–such as the processors, RAM, and graphics card–increase their power consumption and speed, they must be maintained within a given temperature range to prevent malfunctioning, overheating, or damage

Therefore, the cooling system on your PC must be optimal.

Indeed, case size greatly influences cooling efficiency. 

Fan size and type

common sized cooling fans for desktop pcs

There is a greater allowance for a more efficient fan with a larger internal void made possible by a larger case.

Accordingly, when there is minimal or suboptimal airflow within the PC’s internal void, the fan’s efficiency is compromised.

The fan is forced to either pull in air from depleted zones or move at faster speeds to push out air to keep the components cool.

Not only does this overwork the fan and cause inefficiency, but it also results in a noisy cooling system.

A larger cavity provides room for slower, larger, and quieter fans that draw in and push out air efficiently and silently. 

The increased PC sizes can be linked to creating ample room within the internal void to accommodate larger and silent fans that prevent overheating resulting from the higher computing power of modern PCs.

A larger cavity also offers space to hold multiple fans for faster, quicker cooling.

Heatsink size and type

various types and sizes of CPU coolers

A larger internal void also allows installing larger and more effective heatsinks. It provides a larger surface area over which the hot air generated in the cavity comes into contact with the cooling fluid, optimizing the cooling process. 

Therefore, having a larger cavity also means you can install higher power chips on your PC without worrying about the risk of overheating. 

Water-cooling systems

liquid cooling inside a desktop computer

The liquid cooling system takes less space when compared to fans, making it the ideal cooling solution for computers with relatively smaller form factors.

However, the water cooling system still influences the size of the PC case.

For instance, the PC case needs to be large enough to house the weather cooling radiator.

This notwithstanding, computers fitted with multiple fans require larger cases in comparison.

The natural conclusion is that the case size will differ depending on the type of cooling system installed, with some computers having much larger sizes than others. 

The overall impact of case size on the cooling capability

The size of the case has a big effect on your PC’s cooling capability.

However, this is often the case for gaming PCs and/or business-grade PCs which typically clock very high processing speeds and need to be effectively cooled to prevent the risk of costly damage. 

It’s unlikely you’ll need a larger case to accommodate more advanced cooling capabilities for everyday applications and use. 

Finding the right case size for you

One common theme in this article is that larger cases are meant to facilitate better performance and more effective cooling while allowing upgrades and expansion.

However, a bigger case may not be right for you.

The ideal case depends on your specific needs. A bigger case is preferable if you want to upgrade your PC to accommodate greater processing demands or include multiple GPUs.

However, for everyday computing, a smaller case is a bit more practical. 

This small case helps maximize space by offering a range of flexible construction options, all while providing quality playability and powerful airflow.

Another thing to consider is that larger cases tend to be costlier than smaller cases. In general, it’s best to assess your needs first to avoid costly errors. 


Some PC cases are large to accommodate the motherboard form factor, allow space for upgrades, and provide ample room for critical components such as the cooling fans, expansion card slots, power supply unit, and drive bays. 

In most instances, larger PC cases are common in environments where a premium is placed on aspects such as storage space, cooling, and processing efficiency.

This is why such cases are common in business or gaming environments. 

For personal use, I recommend getting a case that is more suited to your individual usage needs and demands.