Upon first glance, you may imagine Network-Attached Storage servers as low-power devices armed with a couple of hard drives. But considering their vast utility when sharing files, creating redundant data sets, and serving media, there are tons of NAS configurations for you to choose from when buying (or building) a prebuilt storage server.

Capable of only supporting SSDs – often those of the NVMe variety – all-flash NAS units are the newest additions to the home server ecosystem, and having reviewed many of these, I have to admit that they have some neat features that set them apart from their HDD-only counterparts. Unfortunately, they have just as many quirks to balance them out, and depending on your specific workload, some of them can be rather deal-breaking.

The good

Blazing-fast transfer speeds

SSDs are a lot faster than their mechanical counterparts, with NVMe drives taking the speed factor to the next level. Let’s say a high-end NAS-certified hard drive can hit around 125-150MB/s (or perhaps 180MB/s, if you go for the cream-of-the-crop HDDs) in transfer speeds. Well, even the more affordable SATA SSDs can easily achieve four times that number, with SATA III allowing for a max speed of 600MB/s. Factor in the extra overhead, and the average speed for a SATA drive is roughly 500-550MB/s.

Then there are NVMe drives, which are on a different level entirely. Most all-SSD NAS units I’ve tinkered with so far cap the NVMe drives to PCIe Gen 3 bandwidths. Even then, a NAS with just one PCIe Gen 3 lane for each drive will still hit 950MB/s. With four lanes per SSD, your NAS can hit around 3500MB/s. To put that into perspective, an all-flash NAS can nearly cap a 10GbE port even when you have a single PCIe Gen 3 lane for each drive – and these servers tend to support multiple drives that you can configure in RAID storage, so even with SMB multichannel enabled on high-speed Ethernet ports, you’re likely to hit the max bandwidth cap with ease.

This makes all-flash NAS rigs perfect for workloads that demand blazing-fast transfer speeds. I tend to use mine for video-editing workloads and, as weird as it may sound, high-speed iSCSI drives to store obscenely large video games. Likewise, they work really well as centralized storage servers for clustered nodes if you’re as deep into the home lab rabbit hole as I am.

Highly portable

Leaving aside their bulky size and loud noise levels, you wouldn’t want to lug HDD-only NAS devices on your travels. Considering the mechanical nature of hard drives, you’d want to protect them from vibrations, as even the slightest bumps can damage them.

Meanwhile, SSDs don’t feature any moving parts, and with NVMe drives being absolutely tiny, all-flash NAS units typically have a small footprint – one that’s comparable to that of your average mini-PC. Compared to the constant whirring and whining sounds made by HDDs, SSD-only servers barely make any noise during operation, making them the perfect companions for your travels.

Terrific energy efficiency

The lower energy consumption of SSDs is another win in all-flash NAS’ favor. To put that into numbers, the average 3.5-inch hard drive uses around 4-10W normally, though this number spikes to 20-25W when the drive spins up when you boot your NAS. Unless you configure the drives to spin down when the NAS is idle (which introduces more problems by wearing them out in the long run), the average 4-bay x86 NAS will consume anywhere between 40-60W during normal operation.

In contrast, SATA drives tend to require 2-4W for average workloads and NVMe drives hog around 3-6W. For idle tasks, their energy consumption lies in decimal units. As such, an all-flash NAS armed with NVMe drives will have anywhere between 10-30W if you run it 24/7.

The bad

Higher cost per TB for SSDs

The low power consumption of your all-SSD NAS becomes pointless once you factor the prices of their storage drives into the equation. Sure, you can get all-SSD NAS devices in the $300-$400 range, which may not seem that high compared to the $250-$350 price tags on budget HDD-only storage servers.

Unfortunately, SSDs are overpriced when you consider the dollar-per-terabyte ratio. I tend to use 4TB hard drives in my NAS, which cost me around $100 (mostly because of the extra taxes). Meanwhile, the average 1TB PCIe Gen 3 SSD costs $50-$60 in my area, with their 4TB variants carrying price tags in the $200-$250 range. That’s a huge price difference if I try to build high-end RAID arrays using my NVMe drives.

The NASty

They aren’t reliable for long-term storage

While the absolutely bonkers pricing of an all-flash setup isn’t terrible if you don’t need too much storage, SSDs are downright terrible if you want to use your NAS to archive data. Unfortunately, that problem is tied to the way SSDs operate. And no, I’m not talking about limited write cycles, because HDDs have mechanical parts that can fail out of nowhere.

The real issue is that SSDs use NAND cells to store data in the form of electrical signals. If you leave these high-speed drives unplugged for too long, their flash cells will start to leak the electrical charge. Couple that with the fact that they are far more susceptible to random shutdowns and power outages than hard drives, and it’s an easy guess why many home labbers and data hoarders prefer bulky HDDs to store essential data.

All-flash SSDs: Equal parts better and worse than their HDD-only rivals

Truth be told, I use both SSD NAS and huge storage servers with HDDs in my home lab. Flash NAS units (and even the datapools created from extra NVMe drives on conventional servers) work well for high-speed workloads, including distributed storage for my clusters. Meanwhile, my HDD-powered RAID pools are responsible for storing backups, media files, and the data generated by my self-hosted application stack.