In Depth: Storage wars: do we really need microSD cards in our phones?

In Depth: Storage wars: do we really need microSD cards in our phones?

Why the microSD may have had its day

MicroSD cards are serious business, or at least that’s the impression given by the uproar surrounding any major Android handset that doesn’t include a slot for one. But are they really necessary?

There’s no denying that they can be appealing. Regardless of how much storage a handset has a microSD card can boost it – and with the launch of SanDisk’s 128GB card it can be expanded massively. That can certainly be useful for anyone who wants to jam their phone full of media, but even if you don’t it’s comforting to have that safety net, knowing that the storage is there if you need it. But do you need it? Really?

You might argue that there’s no downside to having a microSD card slot even if it’s not likely to get used, but that’s not entirely true. For one thing they simply don’t fit with the design ethos of some handsets.


Phones of a certain design, such as the unibody HTC One, can’t easily support a microSD card slot and the design is one of its biggest selling points. To compromise that would be to compromise the whole handset.

Slow storage

Even on phones which can easily fit one in it’s not necessarily desirable. Because while microSD cards sound good on paper in reality they can hugely impact a phones performance.

According to a study carried out by Hyojun Kim at the Georgia Institute of technology, using a microSD card in your phone can cause it to become sluggish, with even basic tasks like web browsing suffering as a result. Overall performance can often drop by between 100% and 300% and in one case the study found that there was an incredible 2000% decrease in performance.

Even at the lower end that’s a massive loss in performance and is an unacceptable trade off for some extra storage, particularly on higher end handsets where you’re paying hundreds of pounds extra for a boost in specs.

The reason for the performance loss is simple, microSD cards themselves aren’t fast enough. They can’t keep up with the power and speed packed into modern smartphones. Though some are better at this than others and the brand and class of card you choose will have a big impact.

microSD card

Bad memory

Speed isn’t the only issue either. In late December, hardware hacker Andrew Huang gave a talk at Chaos Compute Club Congress, where he explained that "flash memory is really cheap. So cheap, in fact, that it’s too good to be true. In reality, all flash memory is riddled with defects – without exception."

The illusion of a contiguous, reliable storage media is crafted through sophisticated error correction and bad block management functions. This is the result of a constant arms race between the engineers and mother nature; with every fabrication process shrink, memory becomes cheaper but more unreliable.

Likewise, with every generation, the engineers come up with more sophisticated and complicated algorithms to compensate for mother nature’s propensity for entropy and randomness at the atomic scale."

Cheap, but not so cheerful

Which brings us to another key issue in the appeal of microSD cards, the fact that they’re cheap. On the face of it the price can be appealing, particularly in comparison to paying through the nose for increased built in storage on a phone.

iPhone 5S

Take the iPhone 5S for example. The 16GB model already retails for a whopping AU$869, but for a 32GB model you’re looking at AU$999. That’s AU$130 more for just 16GB of extra storage, while the 64GB model is yet another AU$130 more expensive.

Admittedly Apple products tend to be expensive anyway, but even a 32GB Nexus 5 costs AU$50 more than a 16GB one and other companies have similar price differences.

Compare that to on average just AU$20 for a 16GB microSD card, AU$45 for a 32GB one or AU$70 for a 64GB one and the pricing does seem quite steep. You could argue that you’re paying the extra for a product which isn’t ‘riddled with defects’ but it still seems like a substantial difference, particularly when you can get a 1TB external hard drive for around AU$120.

Robert Leedham, writer for Which? Tech Daily agrees, saying "microSD cards aren’t essential in phones, but they’re a cheap way to get added storage. Spending AU$20 for 32GB extra space on your mobile is a good deal in anyone’s book."

An argument could certainly be made that manufacturers should charge less for extra storage then, but given how slow and unreliable microSD cards are it’s still often worth paying the extra to avoid them.

Upping the limit

Of course sometimes even paying for a high-capacity handset isn’t enough, as you’re still not going to be getting more than 64GB of storage, which should be more than enough for most people but it’s still easy to fill.

Smartphone storage can be even more limited than it initially appears to be too, as some of the advertised memory is taken up by the operating system and often by apps which can’t be uninstalled.

Leedham sees this as a major problem, arguing that: "Manufacturers will begin to offer more storage space if they think it will make more people buy their phones. Realistically, they need to ensure operating systems don’t eat up too much existing storage space. Our recent storage test found only 8.56GB (or 54%) of a Samsung Galaxy S4 was actually available for you to use."

Sometimes the hit is only a few gigabytes, as on the 16GB iPhone 5S and Nexus 5, which give you 12.20GB and 12.28GB of usable storage respectively, but other times you can be left with only around half the advertised amount, as in Leedham’s example, making a microSD card all but essential.

The good news is that phone storage is increasing. The iPhone 3G had a choice of 8 or 16GB of storage, the iPhone 4 brought the potential storage up to 32GB and the iPhone 5 boosted it to 64GB. If Apple continues that pattern then the next iPhone will have 128GB of storage.

You can see a similar increase among other manufacturers. HTC for example put just 512MB of storage in the Hero, but that went up to 1GB in the Sensation, 16 or 32GB in the One X and 32GB in the HTC One.

iPad Air

That trend is likely to continue, as tablets like the iPad Air now offer 128GB of storage and there’s even a smartphone with that amount of capacity, unfortunately it’s only available in China, but it’s surely only a matter of time before 128GB of storage and beyond become common in phones.

Given the rate that storage has increased so far that’s likely to happen sooner rather than later and when it does microSD cards will become a lot less desirable.

MicroSD: the alternatives

Up in the air

In the meantime there’s at least one viable alternative to microSD cards and in many ways it’s a far more attractive option. We’re talking of course about cloud storage. After all why have your files stored on one device when you could access them from every device you own by uploading them to the cloud.


The pricing compares favourably to microSD cards too, with most providers giving a certain amount of storage away for free, right up to 50GB in the case of Mega. But even subscriptions don’t have to break the bank. Box is one company offering 100GB of storage for not much money at all.

Cloud storage does have its limitations, as uploading large files can take a while and as Leedham points out "your phone won’t always be connected to wireless internet, so internal storage is still important. The interesting thing will be whether apps continue to grow in size, just as flash storage does."

But it’s increasingly rare to be without some form of internet connection on phones and with most major storage providers offering smartphone apps the whole process is normally very easy, while your data is safer than it could ever be on something as unreliable as a microSD card.

Streaming services are another alternative and while they’re even more dependent on an internet connection they take storage out of the equation entirely.


With a Netflix subscription you have instant access to thousands of films, while Spotify gives you access to millions of songs, far more than could ever fit on even the biggest hard drives and you have access to them across all of your devices.

But if you’re particularly attached to your own music collection or don’t want to pay a subscription then there’s always Google Play Music, which allows you to store up to 20,000 of your own songs in the cloud for free and stream them to your devices.

Rob Hodges from believes that phones will be heading even more towards cloud storage in the future, saying that "with all the leading operating systems moving towards cloud storage (Google Drive, SkyDrive, iCloud) content is going to be more off your phone, and more accessible from anywhere.

Cloud accounts can be quite generous for storage meaning you have plenty of space for your major content. Whether apps will have the functionality to be accessed remotely without using memory on your device is the next challenge, but it will be something smartphone manufacturers are trying to conquer."

Right now you can’t store apps in the cloud or stream them, but then you’re increasingly unable to move apps to microSD cards anyway, so that’s not such a factor.

Separation anxiety

Even if the phone and apps you have do allow for it you might want to reconsider, as above and beyond the issues with microSD cards highlighted earlier there’s also the fact that separating an app from OS features on the phones internal storage can cause problems of its own.

Hodges explains it like this: "Downloaded apps need access across a range of the pre-installed OS features. Even the little things like WhatsApp accessing your phone contacts list, or Skype accessing your camera. Building a partition between app memory and OS memory would only slow things down, meaning a more disruptive user experience."

MicroSD cards aren’t all bad of course. Hodges argues that they’re "great for your disposable media files such as music, movies and camera content. Definitely recommended as a way to access your library and can easily be taken out the phone and plugged into business/personal devices.

Should your phone break down, the microSD card is that sigh of relief that your valuable photos and multimedia are safe, easily accessible and can be uploaded to your computer via SD card adaptor or another smartphone."

NAND storage

On the way out

But with phone storage increasing in size and cloud storage taking off they’re increasingly unnecessary. Indeed the HTC product team revealed to us that "external memory such as microSD can add flexibility, however HTC has found customers are using external memory less and less."

As the demand for them goes down we’re likely to see their support go down too. Many smartphones still have microSD card slots right now, but HTC has already abandoned them in its last couple of Android flagships (though the HTC One Max does include one) and if customers really are using them less then other manufacturers are likely to follow suit. Particularly given that both Google and Apple shun them.

Frankly that’s no bad thing. On balance the extra storage space and peace of mind that they give you is not enough to compensate for the damage they can do to your phones performance, while as the internal storage of handsets gets bigger and cloud storage takes off they’re hardly needed anyway.

  • Looking up to the cloud but not sure where to start? Check out our tips on making the most of free cloud storage.