I am thinking to add a faster/better performant M.2 SSD. Currently, I only have a 2.5" SSD. All my OS stuffs and documents are in it. I am thinking to transfer all the OS to the M.2 SSD, but it requires quite a bit of work.

So I am wondering if having a faster SSD to store OS stuffs is going to increase the speed and performance of my laptop at all? What does it affect? If it makes only copying files faster, I don't see a need of doing that.

  • 6
    Just a note: "Perceived increase of performance/speed" will depends highly on your usage. HDD to SSD is a significant change (and very noticable). SSD to m.2 - depends. If the m.2 is PCIe - you might notice difference in speed. But if you have SATA m.2 - then you most likely not notice anything (since it will the same SATA bandwidth)
    – Darius
    Jan 14, 2021 at 23:28
  • 2
    @Darius: 2.5"SSD's also come with the rare U.2 connector, which is how you connect NVMe drives in that form factor. U.2 is more for servers; M.2 has a size benefit in laptops.
    – MSalters
    Jan 15, 2021 at 10:00
  • 1
    "I am thinking to transfer all the OS to the M.2 SSD, but it requires quite a bit of work" - have you already heard about disk cloning?
    – gronostaj
    Jan 15, 2021 at 10:43
  • 4
    Have a looked at performance monitor? If the monitor shows 100% disk use while you are waiting, the waits will be shorter. On the other hand, if time spent on disk use is less, your bottleneck is somewhere else.
    – ojs
    Jan 15, 2021 at 13:59
  • 4
    Watch this video. Tl;dw: the difference between spinning rust and flash is significant; the difference between SATA vs. PCIe 3/4 is much less so.
    – Matthew
    Jan 15, 2021 at 16:13

7 Answers 7


I have a Desktop computer with a decent 1TB Samsung regular SSD drive. It starts very quickly and runs very quickly. It used to have hard drives and the difference in startup and run is very noticeable.

I have a Laptop that came with a 1 TB NVMe drive in an M.2 slot. It has always been very fast.

I frequently put the laptop on a table across from the Desktop. Once a Feature update has downloaded (Desktop on wired Ethernet ; Laptop on wireless), the installation of the update including restart is pretty much the same.

You might see some speed increase if you upgrade, but it may not be really noticeable.

You might leave this project to the next computer.

  • 7
    It is marginally faster but in normal working use, not really noticeable. As noted, I have tested side by side.
    – John
    Jan 15, 2021 at 2:21
  • 3
    @IsaakNewton It should be noted that both are SSDs. You're simply comparing whether they're SATA or NVMe
    – MechMK1
    Jan 15, 2021 at 9:59
  • 4
    Actually a NVMe SSD may be significantly faster than a SATA SSD, but it's barely noticeable because a SATA SSD is already so fast.
    – gronostaj
    Jan 15, 2021 at 10:44
  • 1
    @gronostaj No, it’s usually a case of being barely noticable because you’re almost never working from a cold cache, and therefore most ‘disk access’ actually only ever hits RAM. If you’ve got very little RAM to begin with or have a primary workload that specifically bypasses the OS-level cache, it may provide a significantly more noticeable performance improvement. Jan 15, 2021 at 16:32
  • 1
    @gronostaj It’s a matter of magnitude. Most people notice delays due to cache misses causing the OS to actually hit a hard drive. Most people do not notice delays due to cache misses causing the OS to hit an SSD (which is why it feels so fast), which means that further improvements from getting a faster SSD are often not noticeable because you are not noticing the delay in the first place. Changing delays from 10 seconds to 1 second is very noticeable, from 1 to 0.1 not so much. Jan 15, 2021 at 18:50

The speed of a storage device affects how long things take to load. Whether it's how long it takes your OS to boot up and log in, load stuff in games, moving large amounts of files, etc.

Unless your SSD is performing really bad for some reason, you won't see much of a difference going from an SSD to an M.2 NVMe SSD. With most real world scenarios, the speed difference between the NVMe SSD and the 2.5" SSD is tenths or hundredths of a second.

In some cases, like loading a specific game, the NVMe might be a second or two faster.

You would only see a large upgrade in speed if you were coming from an HDD or a SSHD hybrid drive.


There are two standards for M.2 SSDs: SATA and NVMe.

With SATA, the only difference is the form factor and the shape of the connector. The signaling and expected performance are exactly the same.

With NVMe, the transfer between SSD and mainboard can be faster as there are more parallel lanes on the connector, but for that to be relevant, a number of things need to come together:

  1. all of the lanes need to be connected
  2. the flash memory needs to be faster than the link speed
  3. your workload must be limited by transfer speed

For normal desktop use, the last point is usually the most relevant: loading an OS requires lots of small transfers and the CPU arranging the data in memory in a way that will be useful later. Any complex processing like encoding videos is limited by the CPU as well.

So you would see a difference only if your M.2 SSD is NVMe, not SATA, and you are doing things that require raw throughput with no processing of the data, which in a desktop scenario is basically how fast you can suspend to disk when you have a memory hog application like Photoshop open. So I wouldn't bother.

  • 1
    Strictly speaking, you don't compare SATA to NVMe. You compare SATA to PCIe, and AHCI to NVMe. There are (at some rather early stages) SSDs with a PCIe interface running AHCI protocol.
    – iBug
    Jan 15, 2021 at 17:46

The speed of the SSD will increase the speed of reading, writing and copying files to and from disk. If you are just using office applications you will not notice a substantial difference because the volumes of data being moved to and from disk are not that great, and all SSDs are much faster at opening small files (which is what most if your files will be) then a hard drive.

If you are doing heavy gaming it could help with loading the game data, and if doing things like video editing it could make a significant difference.


A faster disk makes a huge difference for nearly everything since disk is the slowest link after networking. So, everything that is not waiting for the network will be faster.

  • Booting the OS from a faster disk makes a significant difference. Although not 100% proportional to the speed increase of the disk, it scales pretty well.
  • Starting any installed software is faster. The larger the software on disk, the more it will improve.
  • Loading and saving files. Obviously but if you are using software that renders files or performs some type of compression, the advantages diminishes.

Many application these days use temporary files to safeguard against crashes and so even if you are working for a while without saving, a faster disk can improve performance. Even better for these cases, you can move your temp folder into a RAMDISK. This will allow an application to recover in case it crashes but not in the case when the operating system crashes. Size is restricted to available memory, so it depends how much RAM you can spare but of all non-hardware upgrades, this makes one of the biggest differences.


Going from a mechanical hard disk drive to a solid-state drive is going to be a massive uplift in system performance and usability. From a SATA SSD to an NVMe SSD, you will notice very little benefit from the latter except in certain specific tasks.

The reason is latency or the time to fully read or write a file from/to the storage device - in a hard drive this takes relatively long, in an SSD relatively little, and it comes from how these devices are physically constructed. Let's look at a very simplified example of how each of these devices would read a file.

For a mechanical HDD, it has to spin its platters to the location of the first part of that file (seeking). Then it has to read that part. Then it has to spin the platters to read the next part, and on and on until the entirety of the file has been read. If the file is large, and/or split over multiple locations (fragmented), the drive has to do more work, which takes more time. In this case, most of the time is spent by the drive looking for the file, not actually sending the file data to whatever asked for it - the latter gets the file data in drips and drabs until the drive is done, so you have to wait quite a while.

In contrast, a solid-state drive is able to access all the parts of a file almost instantaneously. But larger files will be too big to send at once, so the SSD has to chop them up and send the pieces out to whatever requested them, which is still much quicker than an HDD.

The only difference between a SATA and NVMe SSD is that the latter has more capacity to send that data (bandwidth) - so if you are reading a very large file, NVMe will be faster than SATA. Other than that they will generally perform similarly.

Therefore, there generally isn't any benefit from going from a SATA SSD to an NVMe one. But there is always a noticeable benefit from going from an HDD to either a SATA or NVMe SSD.

  • IIRC, moving the heads takes longer than waiting for the correct sector to be under them. However you are correct, fragmentation affects HDD performance more the SSD
    – CSM
    Jan 16, 2021 at 22:17

The main thing a fast SSD speeds up, is small I/O. A lot of file access comprises small amounts of data, typically 4 kilobytes in size or similar. Hence you'll see in SSD reviews specifications for 4K random reads, and writes - and for good reviews mixed read/writes too (which is the hard one that they don't always report!)

If your computer use "behind the scenes" uses a lot of 4K or small file access, then that's what it will speed up a lot. HDDs are very slow at this kind of file use.

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .