A 1TB drive will still work in a modern PC, but it won't leave you much room to spare. Once that drive starts to fill up, you're not only fighting for space, you're actually making the SSD work harder. That is why you need more than 1TB of storage for a boot drive, especially on Windows.
One terabyte is barely enough
Storage demands aren't slowing down
Your boot drive has to hold more data than just the OS. It typically stores browser caches, game launchers, Windows updates, and all of your documents, pictures, and downloads, unless you manually move them.
Games are especially demanding . A few modern AAA titles can easily eat up hundreds of gigabytes. Virtual machines, local AI models, UHD video, and RAW photos can also use up a ton of space.
That problem isn't getting better either—storage needs only ever go up. Games are getting larger, Windows certainly isn't getting any leaner, and every new generation of phones brings larger photos and videos. Even a software update can use up gigabytes of temporary space just to unpack and replace files.
Additionally, you can't actually use all of that 1 terabyte. Some of it gets used for formatting, and you need to leave a chunk empty for system updates and general SSD health. You aren't really working with a full terabyte of usable space when you account for what you need to do to make a 1TB drive practically useful.
Moving to a 2TB drive makes many of those problems much more manageable. You can keep more of your game library installed and avoid turning storage management into a weekly chore. You don't need to worry about freeing up space so Windows will update properly. As long as you exercise a little bit of restraint, 2TB will be a much better experience over 1TB.
Larger SSDs tend to be faster
Writing in parallel speeds things up
Patrick Campanale / How-To Geek
A lot of an SSD's speed comes from parallelism , where the controller writes data to multiple locations on the drive simultaneously instead of writing one-by-one. The more NAND cells available, the more the controller can divide the workload up.
With the extra cells available to work with on a 2TB drive, the controller has more room to write in parallel, which is especially helpful for sustained workloads. You won't notice your apps opening twice as fast, but there will usually be a difference when installing games or transferring large media libraries.
Bigger drives usually have more cache
Most of the cells in an SSD are found in triple-level (TLC) or quad-level (TLC) configurations, which, in practical terms, just means you can pack more storage cells into a smaller space.
Unfortunately, that has a large drawback: they're usually slower than single-level cells.
To improve the write speeds of SSDs, manufacturers usually force the SSD to treat a small part of its denser TLC or QLC memory as the much faster single-layer cell (SLC) configuration (usually called pseudo-SLC). When you need to write data quickly, it is first sent to the portion that is acting as SLC and then later sent to the slower, denser TLC or QLC storage.
When you have plenty of free space, your pseudo-SLC cache can be larger, so those writes stay fast for longer. If your drive is small or nearly full, that performance drops off much sooner. By choosing 2TB, you ensure you have enough cache to handle real-world without running into a performance wall.
Your SSD can write without waiting
Having extra free space also prevents the SSD from stuttering. When a drive has plenty of empty blocks, it can just write data to a cell and move on. If it's near capacity, the controller has to spend time moving existing data around and erasing old blocks before it can save anything new.
That background cleanup process is normal, but writing is smoother when the drive isn't cramped. A 2TB drive holding the same amount of data as a full 1TB drive has more room to write data without stopping to clear cells first, which means you'll be spared annoying slowdowns during ordinary use.
Larger drives can write more data before they die
Wear-leveling is essential
Patrick Campanale / How-To Geek
Finally, there is the issue of longevity. Since SSDs wear out based on how much data is written to the NAND cells , the controller tries to spread that wear evenly across the entire drive, so one cell doesn't get written to 10,000 times while another goes completely untouched.
It isn't that a 1TB drive is fragile—modern drives are very reliable—but a larger drive will have a higher total write endurance, allowing you to use it longer.
Storage isn't getting cheaper any time soon
When a drive costs nears $200 per terabyte, you need to get the most bang for your buck. Even though 1TB SSDs are less expensive, there are too many concessions you have to make, both in terms of performance and ease of use.
It'll cost more up front, but you're better off buying a 2TB (or larger) SSD once instead of two 1TB SSDs a few months apart when your first drive is completely filled up. There is usually a cost benefit there too—larger drives are usually less expensive per TB of storage than 1TB drives are. In the era of flash memory scarcity, those cost savings matter.
