If you notice your Network-Attached Storage (NAS) running slow after months or years of use, you’re not imagining things. Like a PC, network storage units slow down over time due to various factors, ranging from hardware limitations to bottlenecks at multiple nodes. But you don’t necessarily need to upgrade to a new NAS to fix that — sometimes, a few tweaks on the hardware or software side can make it feel brand new.

Here are a few reasons why your NAS feels slow and how to fix them.

5 CPU bottleneck

If the processor isn’t processing, you’ve got a problem

If you have an entry-level NAS with a dual-core processor, you may have started to notice limitations. Many of these processors aren’t designed for heavy tasks like video transcoding, and over time, handling newer, more demanding apps and workloads becomes even harder.

If your CPU usage is constantly maxed out (you can monitor that from your NAS control panel), there are steps you can take before you go for a NAS upgrade. Offloading video transcoding by pre-converting media files to a standard format can help free up the integrated GPU. Background processes such as media indexing and backups can also push CPU usage to its limits. Scheduling these tasks during off-peak hours can help distribute the workload more efficiently.

Finally, if you regularly run heavier tasks like Docker containers and virtual machines, upgrading to a NAS with a more powerful processor might be necessary, though only after you’ve tried out these optimization tricks.

4 Limited amount of RAM

Upgrading RAM could be an easy and effective fix

Just like with CPUs, RAM bottlenecks can make your NAS feel like it’s crawling even while doing the simplest tasks. RAM enables smooth multitasking and allows multiple apps to run simultaneously. Entry-level NAS models typically come with only 2 GB of RAM, which may be sufficient for basic media streaming but inadequate for handling multiple applications and tasks.

Many NAS enclosures have an extra RAM slot for expansion. Adding a new stick can improve performance significantly without much effort or cost. If your NAS doesn’t support expansion, replacing the existing RAM with a higher-capacity module may be an option — remember to ensure that the existing RAM isn’t soldered to the motherboard and check your NAS's maximum supported memory capacity before upgrading.

If upgrading RAM isn’t feasible, optimizing NAS usage can still help. Things like scheduling security camera footage recording during the night or running backups when no one is streaming 4K movies on the living room TV can ease the strain on the system.

3 Networking bandwidth

How data is delivered to your devices matters a lot

Even if every other component on your NAS hardware is working fine, slow networking speeds can create bottlenecks, making the system feel slow. A 1GbE connection between your NAS and the router maxes out the speeds at 100–120MB/s, which can feel sluggish when handling multiple high-bandwidth tasks.

Some NAS models allow LAN port upgrades using first-party modules. If your unit allows, switching to a 2.5GbE or 10GbE port can significantly improve speeds, granted your router also supports these speeds. If your NAS has multiple LAN ports, enabling link aggregation can effectively double the throughput using two ports at the same time.

You must already know that file transfers over a wired connection are much faster and more reliable than Wi-Fi. So, connecting your NAS directly to your network instead of using wireless can also help increase the transfer speed.

2 RAID could be to blame

Data safety sometimes comes at the cost of speed

RAID setups are an absolute must for data redundancy, but they can also negatively impact your NAS’s performance. Not all RAID configurations are created equally — each offers a different combination of speed and security. For instance, RAID 0 provides the fastest transfer speeds but lacks redundancy in any form, while RAID 5 and RAID 6 offer a better mix of speed and data protection.

If your NAS supports it, switching to RAID 10 can improve transfer speeds, compared to its more mainstream alternatives, while still offering the benefits of redundancy. A good thing about RAID is that it’s flexible, thankfully — you aren’t stuck for life with the configuration you chose during setup and can change it without losing your data. Once you know for sure that the sluggishness is indeed because of RAID, switch to one that prioritizes speed.

1 Storage space constraints

Ignoring the ‘storage almost full’ warning can hurt performance

A nearly full storage pool can slow down your NAS — and it happens to be one of the most overlooked factors when it comes to falling NAS performance. If the available space is almost full, the NAS will naturally start to feel sluggish due to limited caching space, inefficient RAID calculations, and fragmentation.

If your NAS supports NVMe caching, adding a couple of NVMe drives can speed things up without affecting your main storage pool. Besides that, freeing up space by offloading old or infrequently accessed files (or even compressing them for archival) can also help.

Finally, if none of that worked, upgrading to more spacious NAS-specific hard drives remains an option. If your budget allows, switching to SSDs for storage can significantly boost your NAS’s speed and even reduce noise and vibrations, which is crucial if the NAS sits on your desk. However, migrating to new drives requires data backups and can be time-consuming, so plan accordingly.

Make your existing NAS work before upgrading

There are many ways to improve your NAS performance by tinkering with the hardware or software without having to immediately invest in a new model. Trying these optimizations first can help restore your NAS’s original speed and efficiency without hefty expenses. If none of these solutions work, an upgrade may be necessary — but planning for the long-term needs can help prevent running into the same issues again.