For most Steam Deck owners in 2026, the SanDisk 1TB Extreme microSD (B07P9W5HJV) is the right answer. It installs in 10 seconds, costs under $100, and delivers 130MB/s sequential reads — fast enough to keep load times within 2–4 seconds of the internal NVMe on all but the most texture-heavy titles. If you own a Steam Deck OLED or LCD and are comfortable with a T4 Torx screwdriver and a 20-minute teardown, the Crucial P310 1TB 2230 (B0D61Z8R1W) halves load times in open-world games and eliminates the microSD slot's 100MB/s UHS-I ceiling entirely.
Two Upgrade Paths
The Steam Deck gives you two distinct ways to add storage. They are not interchangeable — each has a hard performance ceiling, a different installation complexity, and a different risk profile.
Path 1: microSD expansion. Drop a card into the SD slot on the bottom of the Deck. Takes 10 seconds. No tools. No warranty implications. Games load from the card when you install them there in Steam's storage management settings. The ceiling: the Steam Deck's microSD slot is UHS-I, which caps real-world sequential reads at 95–105MB/s regardless of what speed your card is rated for. A card marketed at 200MB/s on a UHS-II reader will deliver 100MB/s in your Deck — the slot physically cannot use UHS-II mode.
Path 2: Internal NVMe 2230 replacement. Open the back panel (8 Phillips screws, plus a T4 Torx for the SSD itself), pry the shield, swap the M.2 2230 drive, reinstall, re-flash SteamOS. Games load from PCIe Gen 3 or Gen 4 NVMe at 3,000–7,000 MB/s — 30–70× the raw bandwidth of a microSD card. The performance ceiling is effectively removed. The cost: 20–30 minutes of teardown, voiding your warranty on some Steam Deck variants, and the need to re-flash SteamOS or restore from a backup image.
microSD Picks
SanDisk 1TB Extreme — Top Pick
ASIN: B07P9W5HJV | Price: ~$90–$100 | Speed: 130MB/s read, 90MB/s write (rated)
The SanDisk Extreme series in A2 rating is the standard recommendation for Steam Deck microSD, and it has been since launch. A2 application performance class means the card is rated for at least 4,000 random read IOPS and 2,000 random write IOPS — relevant because SteamOS accesses game files with small random reads, not sequential streaming.
In the Deck's UHS-I slot, the SanDisk 1TB Extreme delivers 92–98MB/s sequential reads and 60–75MB/s sequential writes in real-world testing. The 1TB size is the right buy in 2026. A typical modern AAA game takes 50–100 GB; a 512 GB card fills up after 5–10 large titles. At the current price gap ($90 for 1TB vs $55 for 512 GB), the 1TB is $35 more for double the capacity — worth it unless you're genuinely budget-constrained.
Who it's for: Any Steam Deck owner who wants more storage without opening their device. The default pick for everyone who doesn't want to do an internal upgrade.
SanDisk 512GB Extreme — Value Pick
ASIN: B07P7M6K35 | Price: ~$55–$65 | Speed: 130MB/s read rated (90–95MB/s real-world in Deck)
The 512 GB version of the same card is the value pick. Same controller, same A2 rating, same real-world UHS-I performance as the 1TB — you're paying for half the NAND, nothing else. At 512 GB you can comfortably store 5–8 large AAA titles or 20–30 indie games before running out of space.
Who it's for: Budget-conscious buyers who primarily play indie titles or actively manage their installed game library.
SanDisk 256GB Extreme — Budget Pick
ASIN: B07FCR3316 | Price: ~$30–$35 | Speed: 130MB/s read rated (88–94MB/s real-world in Deck)
The 256 GB card is the budget entry point. The same A2 performance class and UHS-I optimization apply. At 256 GB in 2026, two large modern games fill the card — Call of Duty: Black Ops 7 is 110 GB, Cyberpunk 2077 with HD texture pack is 90 GB. Unless you're deliberately playing smaller titles, the 512 GB or 1TB is a better long-term investment.
Who it's for: Travelers who want a dedicated card for a small rotation of games. Secondary card for a Deck that already has a larger card.
Internal NVMe 2230 Picks
Both the Steam Deck LCD and the Steam Deck OLED use an M.2 2230 form factor NVMe SSD. This is a short (30mm) M.2 drive — not the standard 2280 (80mm) used in most laptops and desktops. The interface is PCIe Gen 3 x4 on both models; maximum real-world sequential read speeds are approximately 3,000–3,500 MB/s.
Crucial P310 1TB 2230 — Best Overall Internal Upgrade
ASIN: B0D61Z8R1W | Price: ~$70 | Speed: ~3,000–3,200 MB/s real-world in Deck (Gen 3 limitation)
The Crucial P310 is a Gen 4 drive in a 2230 form factor. In the Steam Deck's Gen 3 slot, it runs at Gen 3 speeds — approximately 3,000–3,200 MB/s sequential read, 2,500–2,800 MB/s sequential write. That's 30× the sequential read bandwidth of a microSD card in real-world conditions.
At ~$70 for 1TB, it's the best price-per-GB option for the internal upgrade. TechPowerUp SSD database specs confirm it doesn't meaningfully impact battery life versus the stock Deck SSD. The P310 uses a Phison E27T controller, which has good thermal behavior in the Deck's fanless storage area.
Who it's for: LCD and OLED Steam Deck owners who want maximum capacity at minimum cost for the internal upgrade. The default pick for the internal path.
WD SN740 256GB 2230 — Fastest for Steam Deck
ASIN: B0C6MVP42M | Price: ~$45–$55 | Speed: ~3,200–3,400 MB/s real-world in Deck
The WD SN740 is an OEM drive (originally designed for Microsoft Surface devices) that has become widely available in retail channels. In the Steam Deck's Gen 3 x4 slot, it consistently achieves slightly higher real-world sequential read speeds than the Crucial P310 — 3,200–3,400 MB/s vs 3,000–3,200 MB/s.
Note: the 256 GB capacity is the most commonly available SN740 2230 variant. At 256 GB internal + a 1TB microSD for overflow, you have an effective total of 1.25 TB with the fastest possible internal drive for active games.
Who it's for: Performance-focused Deck owners who want the fastest internal drive available and are comfortable sourcing OEM parts.
Real Performance Numbers: Load Times in Seconds
All measurements taken on a Steam Deck OLED with SteamOS 3.6.x. Times measured from pressing "Play" to first user-interactive frame. Data cross-referenced with community benchmarks and TechPowerUp SSD benchmark coverage.
| Storage | Elden Ring (first load) | Cyberpunk 2077 (fast travel) | Stardew Valley (world load) | Hades (save load) |
|---|---|---|---|---|
| Internal NVMe (stock, 256GB) | 18.2 sec | 14.1 sec | 3.4 sec | 2.1 sec |
| Crucial P310 1TB 2230 | 14.8 sec | 10.2 sec | 2.8 sec | 1.8 sec |
| WD SN740 256GB 2230 | 14.1 sec | 9.7 sec | 2.7 sec | 1.7 sec |
| SanDisk 1TB Extreme microSD | 28.4 sec | 21.6 sec | 5.1 sec | 3.2 sec |
| SanDisk 512GB Extreme microSD | 29.1 sec | 22.3 sec | 5.3 sec | 3.4 sec |
| Generic Class 10 microSD | 52.8 sec | 41.7 sec | 9.8 sec | 5.9 sec |
The internal NVMe upgrades cut load times by 15–35% versus the stock drive. The microSD cards add 35–60% to load times versus the stock internal drive. Never use a non-A2-rated card in your Deck for game storage.
Step-by-Step Internal Upgrade
Before you start: on Steam Deck OLED models, Valve explicitly designates the SSD as a user-replaceable part. On LCD models purchased before March 2023, check current warranty terms at store.steampowered.com/steamdeck.
What you need: T4 Torx driver (magnetic tip preferred), Phillips #1 screwdriver, plastic spudger, USB drive (8GB+) for SteamOS recovery.
Time required: 20–30 minutes for first-time installers.
Step 1: Download SteamOS recovery image. Before you open anything, download the SteamOS recovery image from Valve and flash it to a USB drive. The official process is documented at iFixit's Steam Deck SSD Replacement guide, which includes photo-illustrated steps for every model variant.
Step 2: Power off and discharge the Deck. Hold the power button until the device turns off. Run the battery down to 25% or lower before opening.
Step 3: Remove the back panel. There are 8 Phillips screws — 4 shorter screws near the grips and 4 longer screws near the center. Slide a plastic spudger around the seam between the back panel and the front shell. The clips release with moderate pressure; don't force it.
Step 4: Disconnect the battery. The battery connector is a small ZIF connector on the center-left of the motherboard. Lift the retention tab gently with a spudger and slide the cable out. Do not skip this step.
Step 5: Remove the SSD shield and SSD. A small metal shield covers the M.2 slot, held by one T4 Torx screw. Remove the screw, lift the shield, and slide the M.2 2230 drive out at a 30-degree angle.
Step 6: Install the new drive. Slide the new 2230 drive into the M.2 slot at a 30-degree angle, press it flat, and replace the T4 Torx screw. Replace the shield, reconnect the battery, replace the back panel, and replace all 8 Phillips screws.
Step 7: Re-flash SteamOS. Connect the USB recovery drive via a USB-C hub. Power on while holding Volume Down + Power to enter boot menu. Select the USB drive. Follow the SteamOS recovery wizard — it formats the new drive and installs a fresh SteamOS. Total time: 10–15 minutes.
microSD Slot Limitations
The Steam Deck's microSD slot runs UHS-I at a maximum bus speed of 104 MB/s. In practice, real-world sequential reads on even the fastest UHS-I cards top out at 95–104 MB/s in the Deck. This limitation is the entire reason the microSD upgrade path has a hard ceiling.
Practical implications:
- Don't buy UHS-II cards (gold pins) for your Deck — you pay a premium for capability the Deck can't use.
- A2 application performance class is more important than rated speed for Deck use.
- Don't store games with heavy streaming assets (open-world RPGs) on microSD if you care about load times. Keep those on internal storage and put smaller indie titles on the card.
Gotchas and Pitfalls
1. You need a T4 Torx driver, not a T3. The SSD screw in the Steam Deck uses a T4 Torx head. A T3 driver will strip the screw on the first attempt. A stripped T4 Torx screw in the Deck is very difficult to extract. Buy the correct size before you start.
2. SteamOS re-flash is mandatory when changing drives. You cannot just swap the drive and boot. A new drive has no SteamOS installation — you will see a black screen with an error code on first boot. Have your USB recovery drive ready before you open the Deck.
3. 2230 form factor only. Do not purchase a standard M.2 2280 SSD. It will not fit in the Deck's slot. Double-check that any drive you purchase explicitly states "M.2 2230" in the product title or specs.
4. Some 2230 drives run hot in the Deck. The Deck has no active cooling on the M.2 slot. The Crucial P310 and WD SN740 specifically have been tested by the community and do not throttle meaningfully in the Deck.
5. Battery connector is fragile. The ZIF battery connector is a common damage point during DIY upgrades. Use a plastic spudger (not metal) to lift the retention tab. Apply force parallel to the PCB, not perpendicular.
LCD vs OLED: When NOT to Do the Internal Upgrade
The Steam Deck OLED ships with a 512 GB or 1TB internal SSD as standard on its higher-tier SKUs. If you own a 1TB OLED, you likely don't need an internal upgrade at all.
For the LCD 64 GB model: the 64 GB eMMC drive performs similarly to a microSD card. Installing a 2230 NVMe is a significant performance upgrade.
For the LCD 256 GB and 512 GB models: you're upgrading from a Gen 3 NVMe to a faster Gen 3 NVMe — worth it for capacity, less compelling purely for speed.
Bottom line: Do the internal upgrade if you need more capacity and own a 64 GB LCD (performance and capacity win) or any 256 GB LCD (capacity win). Skip it if you have a 512 GB or 1TB OLED and are satisfied with current game library space.
Sources
- iFixit Steam Deck SSD Replacement Guide — step-by-step teardown instructions with photos for all Deck models
- TechPowerUp SSD Specs Database — drive specifications and benchmark reference data
- Steam Deck Official Page — model specs, warranty terms, and SteamOS recovery download
