Steam Deck 1TB SSD vs Micro SD Card – Speed, Loading Times & Performance
I love my 1TB Steam Deck – it’s got plenty of space for everything from Steam games to emulation ROMs, but not everyone will want to open up their Deck, nor spend that much on a 1TB SSD, so what about using a microSD card? They’ve come down in price a whole lot, to the point that a 512GB card is under £40 – or in this case $40 for this Sabrent Rocket V30 512GB card. This is rated at V30 video class speed, UHS speed class 3 and UHS-I meaning it can read at least 100MB/s and at least 30MB/s of sustained writes. You’ll find other cards with these ratings claiming up to 150MB/s reads too, which is not bad from such a tiny thing!
Of course, that’s nothing compared to an internal SSD – the one I fitted to my Steam Deck is a Kioxia BG4, a single chip gen 3 NVMe SSD that according to the Deck can offer around 2.3GB/s sequential reads and 1.6GB/s sequential writes. That’s far from the fastest drive you could stick in here, but I already had one to use and it’s more than enough for the Deck. Compare that to the microSD card though, which hit just 91MB/s reads – below it’s claimed performance – and 82MB/s writes. The real killer is actually a couple rows down, the random 4KB block size tests. The SSD can offer 900MB/s reads and 400MB/s writes, compared to just 21MB/s reads and 5.5MB/s writes. Even with a lower queue depth the SSD offers 57MB/s reads and 200MB/s writes, compared to 17MB/s reads and 4.7MB/s writes on the SD card. That’s a considerable difference – but let’s see how that translates into game loading times and even in game performance.
I’ll start with No Man’s Sky – a game that normally takes an age to load anyway. In my testing, from loading my save file to the world loading in and my character being ready to move, on the SSD that took 56 seconds. The microSD card? That was 69% slower at one minute, thirty five seconds. That is a sizable disadvantage. I’m going to let this play out in real time so you can see just how long that actually is and I’ll be back to show the performance differences.
Of course you generally only get that downside on the initial load-in, so once you are in game you should be good, right? Well, because of the slow read speed from the SD card you might find the game stuttering especially when loading in new areas of the world or universe. In the short run-about I did there wasn’t much difference which is fantastic, but for longer play sessions you might notice a bit of a difference. Generally once everything is loaded in you shouldn’t see much of a difference, but there’s no doubt it is a worse experience overall – even if that’s only slightly worse.
Moving on to Cyberpunk, this one is much, much faster. The SD card is still 58% slower, although thanks to the loading time being so much lower at just 12 seconds for the SSD, 58% slower only adds 7 seconds for a total of 19 seconds. For the performance side of things I ran the in-game benchmark and got some rather interesting results. The game is mostly capped at 30 FPS and both basically average to that, but when loading from the SD card the minimum drops to just 20 FPS, compared to 29 FPS from the SSD. That kind of load-in jitter can be a bit of an annoyance, although normally it’s not a gameplay ruining experience.
Lastly we have GTA V, which is a much smaller percentage gap – just 22% slower this time. This is loading story mode, and the SSD takes 27 seconds versus just 33 seconds from the SD card. Again I’ll let this run in real time so you can see the difference.
Interestingly, again I ran the built in benchmark, and while the performance generally remained the same, the loading time between the scenes meant the SD card run took 25 seconds longer than the SSD test. I’ve synced up the tests as best as I can so again I’ll let these run so you can see what’s going on.
While upgrading the SSD in your Deck is a pain, you do get a much better experience overall from it. It does depend on the game, some are going to suffer much more than others, but generally speaking you can expect your games of choice to sit somewhere in the range we’ve seen here. If it isn’t too I/O heavy it might be more like GTA V where it’s really only a minor loading time increase, versus something like No Man’s Sky where you see a significant time increase and potential stuttering from loading in new areas or textures. The good news is that adding a large, fast microSD card is a great way to expand your Deck’s storage – even for games. Things like emulation should work pretty well from the card, and any non-I/O heavy games (think indie games, platformers, that sort of thing) should see relatively little difference.
