I have a spare 120GB SSD kicking around and I was wondering if plugging it in and downloading my Steam games to it would have any performance benefit? Currently I have a 240GB SSD with both Windows 10 and all of my Steam games.

I can't complain about performance but I was just wondering if it would make any difference.


More context #1:

Data loss is not a problem - this is a gaming-only PC with no persistent data - not even game saves. I have a separate machine for work.

More context #2:

Lets focus on games like Arma 3 and GTA, which load the world data as the player explores it.


7 Answers 7


Unless your 120 SSD is really better than your 240 one (if the 120 has a SATA version higher than the 240 for example and your motherboard support it), you won't notice a difference if there's any. It might be a little bit faster under some circumstances.

The main advantage of having a different SSD for your games will be that it won't be accessed when your OS needs to access its own files. When the OS is loaded and its resources are also, it doesn't read/write a lot.

If there is performance difference having your games on your 120 SSD, it will be when your OS also needs to access its own files. That is considering both are on the same SATA version.

If you want the most out of your SSDs, use the one with the fastest read/write speed on small files for your OS, the other for your games.

  • 1
    +1 The last sentence is very important. Focus on that one.
    – KeyC0de
    Commented Nov 26, 2016 at 22:20
  • 1
    One additional bit of context is that, in some edge cases, where most of the game files are very large, an HDD may be faster, as it's one contiguous chunk of data, instead of parts of the file being split up into different areas on an SSD.
    – Zymus
    Commented Aug 18, 2017 at 22:22

Since you're already on SSD, adding another as an extra drive will not improve performance much (if at all). The difference would be negligible unless you had a really bad drive or one that already has bad sectors. Any SSD would be faster than a traditional hard drive.

With that said, you should still consider using it as a game drive instead of using your main OS drive. By doing so, you can prolong the life of your main drive as you're doing less reads/writes to it when playing your games. SSDs won't last forever so you wouldn't want to kill it off too quickly.

If you wanted to actually improve your performance with the extra drive, you'll want to look into setting up your drives in a RAID configuration (e.g., RAID 0). Just be warned that by doing so, depending on the level you choose, you may increase the chances of potentially catastrophic failure.

And if you didn't get the hint, make sure you have backups in any case. Consider a regular high capacity HDD for backups if you don't already have one.

  • I've added more context Commented Jul 16, 2015 at 15:53

If the two drives are on different datapaths, you will notice a substantial improvement. Most motherboards have all drives on the same datapath though (some high end ones have two separate datapaths). If you are looking for an improvement with only a single datapath, you have to find what the maximum thouroughput and average thouroughput of the path is, and see if the single drive is "maxing out" that path. If it's not, another drive will allow faster reading. With SSD's though, you almost certainly have maxed out the datapath, and will not see improvements.

  • How do you determine whether the path is being maxed out? If the OP has a single hard drive, then they might not be able to max out the path. (Feel free to edit your answer at any time to improve it, and flag this comment as obsolete once you have. Welcome to Arquade!) Commented Jul 16, 2015 at 17:51
  • This is true, however you also have to consider if the second drive is slower then at what point will you achieve diminishing returns. Go RAID with a decent controller and you will get the biggest benefit.
    – Brad
    Commented Jul 16, 2015 at 19:54
  • This is really only true if there is significant non-gaming IO from the original SSD during periods when there is gaming IO from the new SSD. Otherwise, you will in no way max out a data path.
    – Eric J.
    Commented Jul 16, 2015 at 20:04

My motherboard has 2 M.2 drives that I use. One a Samsung 970 Pro (1TB) and the other a 980 Pro (2TB). I have an additional Samsung 850 (1 TB) that is used to stage files when I want to move them. I use my 980 as my Primary, with my 970 as the secondary. The speed difference is almost negligible. The 980 is of course faster, but imperceptible at this point. I would offer a different answer than I have seen so far. I use my secondary drive as a layer of security. Separating files that I download from my OS partition and scanning them before execution is a good security practice. If you use your system for gaming alone, do whatever. If you do anything on your computer for administrative work, I suggest separation of your data.

As for speed concerns, if you are not overtaxing the space on your primary drive, you can just partition it and install Steam (or whatever) on your new partition. If you need the extra space, absolutely install on a second drive. Avoid (an ALWAYS rule) reaching less than 10% free space, and you should attempt to always keep 30%, if possible. Make use of your SSD's ability to act as memory for processing.


Here's a different angle than the other answers, or perhaps a slight expansion on something Jonathan Drapeau said in his answer. By having your games on a different hard drive, you allow your OS to use the space more effectively on its own drive. One of the thing modern OS's do is save data from memory to storage(SSD in this case) when it isn't likely to be used in a while. The problem, though, is that as your drive fills up, your OS has a smaller space to save this data, and can end up thrashing.

So, as you download more games you'll eventually, and inadvertently, cause your OS to thrash, which will reduce the performance of your games. If you have your games on a separate drive, your computer won't consider that disk space to be useable for swap/paging and you won't have the problem of thrashing, even if you fill it up to 99%.

For the best performance, I would recommend your OS drive to be your slower driver, and your gaming drive to be your fastest. Many people already do this configuration, and I even have it setup where my OS drive is a spinning HDD and my gaming one is SSD.

  • 2
    The solution to thrashing is more RAM. While it is true that a full drive might not have room to make or expand a page file, most OS have a minimum page file size and it is marked as reserved and cannot be used. Nothing happens in a computer unless it is in RAM. Thrashing is a looping problem where the RAM must be swapped to disk to make RAM available for a priority process, but the next process to be serviced also needs that space, so the first processes memory gets paged, rinse repeat.
    – Yorik
    Commented Jul 16, 2015 at 21:27

Short answer: No. Your 240GB SSD is likely faster than your 120GB one. You could stripe/RAID0 them, but that has implications.

Long version:

You could software-RAID0 (stripe) the 120GB with the 240GB drive, which would get you extra performance, but that'd probably mean you're going to waste 120GB of that 240GB drive, and you wouldn't be able to boot from it anymore. On Linux you'd be able to just use mdadm to RAID0 partitions of the separate drives, and use the spare 120gb of the 240gb disk to boot from and such, but I'm not sure windows could do the same. I'm pretty sure you'd at least have to convert them both to GPT partitions, which means you wouldn't be able to boot from it with win7.. Worth a shot if you know your way around in Disk Management (start->rightclick computer->manage->disk management) that would be a way you could improve performance I guess.

But in practice? If you just plug in an extra 120gb drive and use that instead of the 240gb one, due to the way most SSDs basically RAID0 their NAND internally, your 240GB drive is going to be faster than the 120GB one, so you'd probably see a performance degradation. Although most games don't really max out the performance of SSDs regardless, so the difference would be negligible.

At most, if you're a super heavy multitasker, when you're doing something extremely disk-intensive during gaming, you could see an improvement of using a different disk just because that 120gb drive wouldn't be occupied.


If the OS is using the paging file while the game is loading (not unusual, as other things are paged out to accommodate the game), that will load the SSD considerably. So you'd get a benefit from either a second SSD or turning the pagefile off - provided you have enough RAM. The latter used to be recommended on SSDs to extend the lifetime.

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