There must be more than that, another explanation, if they are slow. Ten year old CPUs were plenty fast already, far more than enough even, to power an NAS device.
My Windows 11 often takes many seconds to start some application (Sigil, Excel, whatever), and it sure isn't the fault of the CPU, even if it's "only" a laptop model (albeit a newish one, released December 2023, Intel Core Ultra 7 155H, 3800 (max 4800) Mhz, 16 Cores, 22 Logical Processors).
Whenever software feels slow as of the last 1+ decades, look at the software first and not the CPU as the culprit, unless you are really sure it's the workload and calculations.
You are correct that the software should perform better, but I don't think the average buyer understands this - they buy a new (and sometimes quite expensive) device, yet it feels sluggish for them, so they feel like they bought a bad product.
Another factor related to speed is that, they didn’t allow using NVMe slots for storage pool until recently for new models (in 920+ still you can’t do that; even if they allowed it, the limited PCI lanes of that CPU would limit the throughput). So a container’s database has to be stored in mechanical HDDs.
Again other companies moved on, and I remember there were a lot of community dissatisfaction and hacks, until they improved the situation.
Their hardware is limited already, and they also artificially limit it further by software.
They changed course now, and allow using any HDD. Will DSM display all relevant SMART attributes? We will see!
On a DS920+ users will run various containers, Plex/Jellyfin, PiHole, etc. The Celeron J4125 CPU (still used in 2025 on the 2 bay DS225+) is slow when used with the stuff most users would like to use on a NAS today, and the software runs from the HDDs only. Every other equivalent modern NAS is on N100 and can use the M.2 drives for storage just like the HDDs, which makes them significantly more capable.
That depends on the CPU… Some are optimised for power consumption not performance, and on top of that will end up thermally throttled as they are often in small boxes with only passive cooling.
A cheap or intentionally low-power Arm SoC from back then is not going to perform nearly as well as a good or more performance oriented Arm SoC (or equivalent x86/a64 chip) from back then. They might not cope well with 2.5Gb networking unless the NICs support offloading, and if they are cheaping out on CPUs they might not have high-spec network controller chips either. And that is before considering that some are talking to the NAS via a VPN endpoint running on the NAS so there is the CPU load of that on top.
For sort-of-relevant anecdata: my home router ran on a Pi400 for a couple of years (the old device developed issues, the Pi400 was sat waiting for a task so got given a USB NIC and given that task), but got replaced when I upgraded to full-fibre connection because its CPU was a bottleneck at those speeds just for basic routing tasks (IIRC the limit was somewhere around 250Mbit/s). Some of the bottleneck I experienced would be the CPU load of servicing the USB NIC, not just the routing, of course.
> far more than enough even, to power an NAS device.
People are using these for much more than just network attached storage, and they are sold as being capable of the extra so it isn't like people are being entirely unreasonable in their expectations. PiHole, VPN servers, full media servers (doing much more work than just serving the stored data), etc.
> There must be more than that, another explanation
Most likely this too. Small memory. Slow memory. Old SoC (or individual controllers) with slow interconnect between processing cores and IO controllers. There could be a collection of bottlenecks to run into as soon as you try to do more than just serve plain files at ~1Gbit speeds.
The Synology DS925+ for example does not have GPU encoding. For an expensive prosumer-positioned NAS this is crazy. They can't let us have both 2.5gb NICs and a GPU.
