ASUSTOR NAS memory spans three DDR generations. The new Lockerstor Gen3 and Flashstor Gen2 take DDR5 SODIMM, the Lockerstor, Flashstor and Nimbustor Gen2 lines take DDR4 SODIMM, the Lockerstor R Pro rackmounts take full-size UDIMM, and the older AS50 to AS70 series use DDR3. Reaching the slots also differs from one family to the next. This guide covers which memory each ASUSTOR takes, how the install goes, and what to check if the NAS does not start.
Which memory does your ASUSTOR take?
Match your exact model, shown on the label under the unit and in ADM under System Information, to the table. Every model links to its NEMIX listing, and the listing names the module type, speed and ECC type ASUSTOR specifies for that unit. The suffix matters: a Lockerstor 4 Gen2 (AS6704T) and a Lockerstor 4 Gen2+ (AS6704T v2) are listed separately, as are the Lockerstor 4 Gen3 and the older Lockerstor 4.
DDR3, DDR4 and DDR5 are keyed differently and do not fit each other's slots, and SODIMM and UDIMM are different sizes. On the DDR5 SODIMM models, both ECC and non-ECC listings are shown. Reviews report that the Lockerstor Gen3 and the Flashstor 12 Pro Gen2 ship with an ECC module and that the Flashstor 6 Gen2 ships with a non-ECC module, and that non-ECC memory works in the Gen3 at the cost of ECC protection. Pick the type that matches your model and your needs, and do not mix ECC with non-ECC. The ASUSTOR NAS memory guide covers every model in more detail, and you can search by ASUSTOR part number in the ASUSTOR part number collection.
Before you start
- Check what ASUSTOR offers for your model. ASUSTOR sells its own RAM modules as accessories and publishes memory install videos for several models. NEMIX RAM modules are researched, matched, and compatibility-tested by NEMIX RAM and are backed by a lifetime warranty, and each listing is built to the module type and speed ASUSTOR specifies for the model. Check ASUSTOR's warranty terms for your region if that matters to you.
- Buy the speed listed for your model. On the Nimbustor AS5202T and AS5304T generation, ASUSTOR specifies DDR4-2400, and one reader of a published upgrade guide reported that a DDR4-2666 module did not work. Match the listing rather than buying the fastest module.
- Keep the original module. Store it in an anti-static bag. If the NAS does not start with the new memory, putting the original back confirms the unit is healthy.
- Match the module count to the slots. Fill two-slot models with two matching modules, or replace the factory module on a model that ships with one. Do not mix ECC and non-ECC.
- Back up your data and have a small Phillips screwdriver and a clear, soft work surface. A reviewer notes that ASUSTOR does not supply a screwdriver or spare screws for the Flashstor Gen2.
- Power the NAS down completely. Shut it down from ADM, wait until it is off, and unplug the power cord and every other cable before you open it.
How to install memory in an ASUSTOR NAS
Step 1: Note the current memory
Sign in to ADM as an administrator and open System Information. Write down the memory total. You will check the same page after the upgrade.
Step 2: Shut down and unplug
Shut the NAS down from ADM, wait until the power light goes out, then unplug the power cord and the network and USB cables. Do not change memory with the power on.
Step 3: Open the unit
This is the step that differs by family, so use ASUSTOR's own video for your model. ASUSTOR publishes memory videos on its tutorial videos page for the Flashstor Gen2, Lockerstor Gen3, Flashstor, Lockerstor Gen2, Lockerstor 10 Pro, and Nimbustor 2 and 4. Published reviews and guides report these layouts:
- Lockerstor Gen3. One review describes removing three screws at the back and taking off the metal case to reach the board. Follow the ASUSTOR Lockerstor Gen3 video to find the memory slots.
- Lockerstor Gen2. After the outer casing comes off, a review reports a heat-reflective plastic layer covering the board, with the processor and memory beneath it.
- Flashstor Gen2. A review of the Flashstor 6 Gen2 describes removing the panel that holds the 80mm fan (four screws) and then more screws to reach the memory. The memory is not reached through the same opening as the drive slots.
- Nimbustor 2 and 4. Two published guides differ. One removes the four drive bays and finds the memory slot beside the power button side. The other loosens three screws at the back and slides the cover off. Check the ASUSTOR video for your unit.
For the rackmount R Pro models and the older AS50 to AS70 series, use the ASUSTOR hardware installation guide for your model, or send us your model and we will tell you what we know before you open it. If your model needs more than a cover removed, take photos as you go so you can reassemble it.
Step 4: Release the old module if replacing
For SODIMM, push the clips on both sides outward and the module pops up at an angle. Lift it out by its edges. For a full-size UDIMM, open the latches at both ends of the slot and lift the module straight out. Do not touch the gold contacts.
Step 5: Seat the new module
Line up the notch in the module with the notch in the slot. For SODIMM, insert the module at an angle and press it down until the clips click. For UDIMM, press both ends straight down until the latches lock. If you are filling a spare slot, use the empty slot and leave the factory module in place when the capacities match. The module should seat without force. If it resists, check the orientation and the memory type.
Step 6: Reassemble and power on
Refit the cover or panel and every screw, put the drive bays back in their original positions, reconnect the cables and press the power button.
Step 7: Confirm the new total in ADM
Sign in to ADM and open System Information again. The memory total should show the new capacity. Leave the NAS under your normal workload for a while and check that it stays stable.
If the NAS does not start or shows less memory
- Shut down, unplug the power cord and open the unit again.
- Reseat each module until it is fully seated.
- Check the memory type against the table: DDR3, DDR4 or DDR5, SODIMM or UDIMM, ECC or non-ECC, and the speed listed for your model.
- Try one module at a time. If a single module works and the pair does not, the pair may not match.
- If the unit powers on but ADM does not load, remove the new module and start with the original, then tell us your model and we will help with the right module.
How much memory should you install?
File sharing and backup run well on the factory memory. Docker containers, virtual machines, Plex or Jellyfin, surveillance and SSD caching all benefit from more. The DDR5 Gen3 and Flashstor Gen2 models take up to 64GB, the Lockerstor R Pro Gen2 rackmounts up to 192GB, and the Gen2 DDR4 models only 16GB, while the AS50 to AS64 DDR3L models top out at 8GB. Do not exceed the maximum ASUSTOR specifies for your model.
Find your memory
- ASUSTOR NAS memory upgrades by model, every ASUSTOR listing.
- The ASUSTOR memory hub page and the ASUSTOR memory guide.
- By type: DDR5 ECC SODIMM, DDR5 non-ECC SODIMM, DDR4 non-ECC SODIMM and DDR4 ECC UDIMM.
- Other brands: NAS memory by brand.
Buying for several NAS
NEMIX RAM is a US-based memory specialist, in business since 1993. Every module is researched, matched, and compatibility-tested by NEMIX RAM, is JEDEC-compliant, and is backed by a lifetime warranty. Offices, schools and integrators that run several ASUSTOR units can standardize on one kit per model. Purchase orders, net terms and volume pricing are available. Request a quote with your NAS models and quantities, or contact our sales team.
NEMIX RAM is an independent memory supplier and is not affiliated with ASUSTOR. ASUSTOR, Lockerstor, Flashstor, Nimbustor and ADM are trademarks of their respective owners, used only to identify compatible systems. Layouts are summarized from published reviews and guides and ASUSTOR's video list; follow the instructions for your exact model.