You would probably assume that the faster your storage, the faster your PC will feel, and to a degree, that's certainly true. If you have an HDD in your PC and upgrade to an SSD, you'll almost certainly notice the difference immediately... but when do those benefits stop being noticeable? And why?

There are a few reasons why you'll start to see diminishing returns as you scale up your storage speeds, and some of them you may never have thought of before. Even if you have a blazing-fast SSD, its advertised speeds of 10,000 Mbps (or more) aren't all that matters.

5 Programs rely on more than just storage

Your CPU and RAM play a part, too

When you launch an application on Windows, your mouse click starts a process where the Windows NTFS locates the file and its resources on the storage device, such as an SSD. Windows reads the file header of the application, which contains metadata about the program, the entry point of the application (so where it starts), where sections of the executable are stored in the program's layout, and more. Windows will then allocate space in virtual memory for the program and map its sections, split into code and data.

Following this, Windows will now check for any files, such as Dynamically Linked Libraries (DLLs) that the program needs, loading them into memory and updating pointers in the program to reference where those DLLs are. A virtual address space is then created for the process so that it can't be interfered with, and memory pages are created and mapped to physical RAM when needed.

Finally, the OS creates an execution thread for the process, specifying the aforementioned start point, sets up the runtime, and the CPU begins to fetch, decode, and execute instructions from the program's code section. Other tasks, like asset or resource loading, may happen asynchronously, depending on how the program is designed.

While there are several steps of this process that are heavily reliant on storage speed, you may have noticed that there are significant parts of this process that are just as dependent on your CPU and your RAM. For example, if your RAM is full, your PC will need to use swap memory significantly more which will slow things down. Plus, if your CPU can't keep up with the speeds of your SSD, then no matter how fast your SSD is, things still won't get done until your CPU is finished with what it was last doing.

4 Random access speeds matter more than sequential

It all depends on where files are

When you buy an SSD and it mentions some crazy fast speed that it's capable of, what you're actually seeing is the sequential read speed that it's capable of. This is basically how fast it can read data side by side, as it's stored in order. This sometimes works for games that have large asset files that your PC will need to load, but for large programs split across a lot of libraries and parts, your random access speeds will matter significantly more.

To put things into context, a PCIe 5.0 SSD in some conditions can have similar performance in random read speeds to a PCIe 4.0 SSD, despite the incredibly high random read speeds touted by PCIe 5.0 SSDs. While 5.0 SSDs are typically faster, it's not something you'll notice, and in the worst of circumstances, 5.0 SSDs can highlight why random access speeds are so important, especially if you don't see any speed improvements from upgrading your hardware.

3 Program optimization

Older programs might not use SSDs effectively

Not every program was built with incredible speed in mind, and this may be exposed by older programs in particular. Applications and games that were developed using inefficient file access methods may not be able to scale up efficiently with faster storage, and developers may have prioritized compatibility over speed when it comes to loading resources.

Coding for SSDs is a pretty in-depth doctrine. While Windows will handle a lot of it for you (along with other operating systems), there are some things a developer can take into account if they really want their applications to perform well on one. This is definitely one of the more minor points in this list, but if a developer doesn't take full advantage of an SSD, you might stop seeing performance improvements as time goes on.

2 Thermal throttling

PCIe 5.0 SSDs can get hot

If you buy a shiny new PCIe 5.0 SSD, then you might be aware that those SSDs can get hot. There are active cooling solutions you can get for them, but the thing as well is that they can thermally throttle over time if you don't keep them cool. That means your SSD, capable of 12,000 MB/s read speeds, might perform worse than a PCIe 4.0 SSD as time goes on if you don't cool it correctly.

This is obviously an extreme example, but it's something you'll need to watch out for. If you're not sure whether you can keep a PCIe 5.0 SSD cool, then you might actually get worse performance out of an upgrade.

1 Lane sharing can decrease your GPU's speed, so you might want PCIe 4.0 anyway

It doesn't really matter, though

If you have a PCIe 5.0 SSD and you don't have enough lanes in your motherboard to support it and a GPU, then there's a chance you might hamper your GPU's performance in doing so. Realistically you won't, but you should be mindful that placing a GPU into a PCIe 5.0 x16 lane will mean that it downgrades to a PCIe 4.0 x8 lane while your SSD is in a 5.0 slot.

The reason this happens is that no GPUs out there use PCIe 5.0 yet, and the primary PCIe slot in modern motherboards is a 16-lane PCIe 5.0 slot. This means that when your SSD takes up some of those lanes, your motherboard will downgrade the slot to a PCIe 4.0 x8 slot. This isn't really a big deal, but it's something to keep in mind and a trade-off that you'll need to make.

If you're not a fan of that, you may need to put your shiny new SSD into a PCIe 4.0 slot, which means that you won't see as many speed benefits as you would have. PCIe 5.0 still doesn't matter for most people, though.