The microSD card slot is located on the bottom of the Steam Deck, beneath the right speaker. | Photo by Vjeran Pavic / The Verge
If you get a Steam Deck, slide in a microSD card, format it, and begin installing a game, you might notice something: incredibly slow download speeds. Like “Is my internet broken?” speeds. There seems to be something happening for some Deck owners, including myself, that prevents your removable microSD storage from being able to operate at full speed.
There is a fix for it that doesn’t take too long, but note that you’ll need to reformat your microSD card during this process, so you will lose your game installs and anything else you have stored on your card.
But first, a disclaimer that it’s possible that your microSD card is, in fact, what’s slowing things down. My colleague Alice Newcome-Beill tells me that you should buy one that has a U3 write speed and an A2 application class (those little symbols will be inscribed on the card), which means that it has higher random read and write speeds than bargain-bin microSD cards. Sadly, some people receive fake microSD cards that either do not have the advertised speed or capacity.
If your model meets that recommendation but you’re still encountering slow download speeds, here’s a smart and well-documented solution to this problem that worked for me (and apparently many others). It can be found within the Steam forums, thanks to a user that goes by RoyalMetalKnights. It involves many steps, but it doesn’t take a particularly long time to do.
(Note: Absolutely none of the valor of figuring this out belongs to me, but I’m going to post it here for easier viewing and to give this good advice another place to live. I’ve made slight adjustments to the wording for clarity purposes, and I’ve added screenshots to make it easier to follow for beginners.)
How to fix your slow download speeds
Once your Steam Deck is powered on, follow these steps. (Again, take note that you’ll be completely formatting your microSD card, so it’s probably a good idea to first make a backup first. You can do that by copying and pasting your microSD card’s contents to a folder on a computer or onto a cloud storage service.)
On the Steam Deck, hit the “Steam” button, then navigate down to “Power,” and finally tap “Switch to Desktop.”
Hit the Steam hardware button, select Power, and then select Switch to Desktop on the pop-up.
In Desktop mode, click the Steam Deck logo in the bottom left corner of the screen.
Tapping the Steam logo will bring up this Start menu-esque window.
Select System on the left side, then on the right, select KDE Partition Manager. (This feature was preinstalled.)
Once that opens, take note of the two options shown under Devices: one will be mmcblk0, and the other will be the name of your internal SSD. (For example, my 64GB SSD says “E2M2” next to it.)
Note that the first drive listed within KDE Partition Manager is my microSD card, though this may not reflect what your screen will look like.
By default, the SD card (mmcblk0) should be selected. If not, select it.
In the top-right area of the screen, it will show a visualization of your SD card partitions. To make sure that the correct storage device is selected, underneath, there should be a little blue box next to ext4 and under Type and a lock icon under Mount Point. The Size storage space shown should reflect something similar to your microSD card’s capacity.
In this screenshot, I’ve selected the bar of info containing the drive’s details, which is necessary to do before you right-click it (or pull on the left trigger) to open a drop-down menu.
Using the right trackpad to hover over that bar of information, pull the left trigger to show a drop-down menu.
Select Unmount.
Press the left trigger again while hovering over the same spot and select Delete.
This screenshot shows the “Delete partition” note within the “Pending Operations” box. Proceed with caution here.
At the bottom of the screen, in the Pending Operations box, it should say Delete partition — it should not say Shred. If it doesn’t say Delete, hit Undo to go backward in the process.
Once you’ve confirmed that it says Delete Partition, then in the top-left corner of the screen just below File, look for and click the button that says Apply.
Here’s the point of no return for reformatting your microSD card.
A pop-up will appear asking if you want to apply the Delete partition operation. Select the Apply Pending Operations button.
Once the operation concludes, press OK.
In the middle section of the screen that shows partition information, it will now show the words Unallocated and Unknown and the overall microSD card size.
Hover over that, then pull the left trigger to bring up the drop-down menu.
Select New from the drop-down menu.
In the pop-up, change the File System option to ext4 and click OK.
Press the Apply button in the top left corner of the program.
A pop-up will appear. Press the Apply Pending Operations button.
It will take about 50 seconds to create a new ext4 partition. After it’s done, your Desktop will pop up a Disk & Devices alert showing a new microSD card was inserted.
Hit OK on the other pop-up box in KDE Partition Manager, then close the app by hitting the X button at the top-right corner.
Double-click or tap the Return to Game Mode icon on the Desktop
Once you’re back in Game Mode, eject your microSD card and reinsert it (the Deck initially won’t recognize that it’s inserted until you do).
After reinserting your microSD card, you’ll want to make sure that you set it as default for future installs by highlighting it, then hitting the X button.
Click the Steam hardware button and go to Settings.
Scroll down to Storage and click into it. It should show your Internal Drive and MicroSD Card. The microSD Card should have a gold star next to it, meaning it’s the default installation drive. If not, hover over it and hit X to Make Default.
Finally, install a game, then hit the Steam menu button and go to Downloads to watch the progress, download speed, and disk usage speed — all of which should hopefully show improved speeds.
Thanks again to RoyalMetalKnights for originally posting this helpful guide.