TerraMaster F4-425 Pro: 30-second reviewTerraMaster has been making NAS hardware long enough to know that the upgrade cycle is everything. The F4-424 Pro arrived in early 2024 with a strong hand: an Intel Core i3-N305, 32GB of DDR5, and a build that put competitors under genuine pressure. Two years on, the company returns with the F4-425 Pro, and the result is a more complicated story than a straightforward generational step forward.On the hardware side, the headline changes are meaningful. Dual 5GbE replaces the F4-424 Pro's dual 2.5GbE, which doubles the theoretical single-client throughput ceiling. The M.2 slot count increases from two to three. Both are welcome improvements that justify the refresh.But there is a wrinkle. The processor moves from the Core i3-N305 to the Intel N350. The N350 is also an 8-core chip, and its maximum burst clock of 3.9GHz fractionally exceeds the N305's 3.8GHz. The difference is that the N350 is an Atom-architecture Alder Lake-N part rather than a Core-class one. Per-core performance and integrated GPU capability are both lower. The advantage is better power efficiency, but some will see this as a retrograde step.The other major story for this platform is TOS 7. TerraMaster has rebuilt its operating system around an AI-first philosophy, with the OpenClaw assistant promising natural language control over 90% of common configuration tasks. That skirts the whole AI backlash, and those who don’t want to chat with their NAS, but equally, there are some that will embrace these features.At £639.99, the F4-425 Pro sits in a remarkably competitive bracket. The Ugreen DXP4800 Pro offers a Core i3-1315U and a single 10GbE at £689.99. The Ugreen DXP4800 GT delivers dual 10GbE and ECC memory support at £589.99. The TerraMaster undercuts or matches both on M.2 count and brings a genuinely new OS story to the table. Whether that is enough depends on what the buyer most needs, but on spec alone, this isn’t one of the best NAS in this sector.(Image credit: Mark Pickavance)TerraMaster F4-425 Pro: Price and availabilityHow much does it cost? From $680/£586When is it out? Available nowWhere can you get it? Direct from TerraMaster or through an online retailerThe F4-425 Pro launched on 23 June 2026, available direct from TerraMaster, as well as retailers including Amazon.com, Amazon.co.uk, and B&H Photo.At the time of review, the 8GB model is priced at $640 / £640 from TerraMaster and Amazon. Online retailer B&H Photo wants $644.99. And all these prices are without drives, obviously.One curiosity is that although the F4-425 Pro spec is for a system that uses the Intel N350 and comes with 16GB of RAM, TerraMaster also has a second SKU with the N305 CPU that its predecessor used, and 8GB of DDR5. This lower spec model is priced at $559.99.The top SKU price matches the F4-424 Pro's UK debut cost, interestingly.For the purpose of this review, we’ll focus on the N350 model, since that was the one that TerraMaster supplied us.Given the price is similar to its predecessor, the networking upgrade from 2.5GbE to 5GbE and the additional M.2 slot make this solution an attractive option over the F4-424 Pro, even if neither is exactly a bargain. What seems odd is that the release of the F4-425 Pro hasn’t made the previous F4-424 Pro any cheaper, unfortunately. More than a disappointment for budget-conscious buyers, TerraMaster is asking $687.99 USD for that previous design.That pricing suggests TerraMaster thinks it's competing with itself to some extent, but recent releases in this NAS space strongly contradict that notion.Ugreen had the DXP4800 Plus, added the DXP4800 Pro and now the DXP4800 GT.Direct from Ugreen, the DXP4800 Plus is $583.99, the DXP4800 Pro is $639.99, and the new DXP4800 GT is on sale for $527.99. Given that all of these have more powerful processors than the TerraMaster F4-425 Pro, and the DXP4800 Pro has a 10GbE LAN port, TerraMaster's pricing seems oddly out of touch.As this is a NAS review, it’s the law that I must mention Synology, even if this company has all but abandoned the SOHO NAS space. After an implausibly long delay between releases, Synology launched the Synology DS925+, a NAS that’s powered by the ancient AMD Ryzen V1500B. Oddly, given this brand's history, it is the cheapest option at $511.99. However, the DS925+ comes with only 4GB of RAM, its dual M.2 slots accept only Synology-branded modules, and the best LAN ports are only 2.5GbE.Given these alternatives, and some others I’ve not mentioned, the F4-425 Pro seems overpriced and underspecced, a phrase I thought I’d never use in reference to TerraMaster hardware.Value: 3.5 / 5(Image credit: Mark Pickavance)TerraMaster F4-425 Pro: SpecsItemSpecCPU: Intel N350 8-core 8C / 8T (Gracemont E-Cores)GPU: Intel UHD Graphics 770 (32 EUs)RAM: 16GB DDR5 non-ECC SODIMM, expandable to 32GB via SO-DIMM swapSATA Storage: 4x 3.5/2.5-inch SATA IIIM.2 Storage:3x M.2 NVMe (both PCIe Gen 3 x1Ports:3x USB-A 3.2 Gen 2 (10Gbps) 1x USB-C 3.2 Gen 2 (10Gbps) 1x HDMI 1.4Networking: 2x 5GbE RJ45OS: TOS 7File Systems:EXT4, BtrfsMaximum Capacity:152TB (4x 32TB + 3x 8TB M.2)RAID Modes:TRAID, TRAID+, RAID 0/RAID 1/RAID 5/RAID 6/RAID 10PSU: 12V 7.2A 90W externalPower Consumption:45W under full SATA LoadDimensions: 186 x 277 x 277 mmWeight:2.9kg (including PSU, but without drives)Warranty:2 YearsTerraMaster F4-425 Pro: DesignStandard TerraMaster CaseNo lockable traysDual 5GbE LANTriple M.2 slotsThe F4-425 Pro continues the black motif TerraMaster adopted with the 424 series, and I do prefer this look to the all-silver devices of the past.The outer shell gives the chassis a denser feel than the silver-and-aluminium aesthetic of earlier TerraMaster NAS units. The front face is clean and largely featureless: four drive bays with activity LEDs behind a pattern of small holes, and TerraMaster branding on each bay.Even without drives, this is a hefty item measuring 186 x 277 x 277 mm with a net weight of 2.9kg. That is compact for a four-bay unit, which is marginally smaller than the same type from Ugreen or Synology.Drive installation remains tool-free for 3.5-inch mechanisms. But 2.5-inch mechanisms still require screws to seat, and aren’t the best design I’ve seen. Firstly, there is no lock to stop an accidental press from disconnecting a drive. And, given how long TerraMaster has been making NAS, you’d think that trays with numbers on them might have made it onto its devices.Admittedly, TerraMaster does provide labels for you to stick on the drive facias, but since they took the time to emboss "TERRAMASTER " onto the plastic fronts of the trays, you think they could also put 1, 2, 3, and 4 on them.I can’t recall when I first complained about the lack of tray locks on TerraMaster NAS, but it was so long ago and so often repeated that its failure to fix this is evidently not unintentional.Another place where TerraMaster does its own thing is with respect to the M.2 slots, where this new model has three and not the two that the F4-424 Pro came.On Synology and Ugreen NAS, the M.2 slots are accessible behind a panel held in place with a couple of screws. But here, there are four screws to remove, and then the entire outer shell of the case slides off. This does provide great access, but I suspect this was done as a cost-saving measure, mostly.Having three M.2 slots sounds wonderful for those with spare NVMe drives to populate them, although that’s tempered slightly by their PCIe Gen3x1 bandwidth allocation. But what I found slightly shocking inside is that the 16GB DDR5 SODIMM is in a single slot. Therefore, if you want to upgrade the RAM to 32GB, you will be forced to remove the existing 16GB module. I’ll talk more about memory later, because the memory controller on the N350 has some odd features. (Image credit: Mark Pickavance)Moving on to external hardware features, having reviewed the latest Ugreen NAS recently, the number of ports on the F4-425 Pro seems on the low side.On the front is a single USB 3.2 Gen 2 Type-A port, and there is no card reader of any variety. The rear has another two USB 3.2 Type-A ports, both of which are 10Gbps, and a single USB-C that is also the same USB spec. And, there are two 5GbE LAN ports and a single HDMI output.There is no USB4 or Thunderbolt, and no PCIe slot to add a 10GbE card. You can channel-bond the two 5GbE ports, but there aren’t many switches that support 5GbE at this time.Cooling is provided by a 120mm system fan that sits centrally at the rear. In smart mode, it adjusts speed to drive temperature. TerraMaster quotes 20.9dB(A) at standby with four SATA drives fitted, which is a quiet figure. And, this system is quiet in typical use.Overall, my takeaways are that this platform is better in some respects than the N305-based F4-424, but each enhanced feature comes with a caveat, it seems.Design: 4 / 5TerraMaster F4-425 Pro: FeaturesDifferent CPUSingle PCIe lane M.2 slotsMaximum of 32GB5GbE LAN portsDue to Intel's endless rebranding, the chip in the F4-424 Pro was a Core i3 N305, whereas the one in this NAS is a Core i3 N350. So like Thor in Ragnarok, it lost an eye, but gained something else.In reality, these chips are remarkably similar, since they both use eight Gracemont E-Cores, have an identical 6MB cache, and a single memory channel for DDR5 memory.But there are two important differences, the first being that the N350 is capped at 7W of base power, not the 15W of the N305. And to conserve power, the N350 can drop the base clock to only 100 MHz when the system is idle. There are also some enhancements to the GPU clocks to deliver a little more speed, but the Intel UHD Graphics 770 (32 EUs) doesn’t have gaming potential.The switch to this architecture over the previous one focuses on making this NAS quieter, less power-hungry, and cooler. That makes perfect sense, even if it's slightly at odds with the headlong charge towards AI that TOS 7 is mustering.What the processor change doesn’t address is that this platform is pinched for PCIe lanes, since both the N305 and N350 have only nine PCIe 3.0 lanes.That goes some way to explain why the M.2 slots are only single-lane and can only achieve roughly 1GB/s, irrespective of what modules you put in them. As a side note, with these performance restrictions, there seems little point in using expensive NVMe drives in this system.If we assume that each of the M.2 slots gets a lane, and each of the 5GbE LAN ports another one, and the SATA ports one lane, and the USB another four, then that’s ten, and we only have nine lanes. That infers a PCIe switch is used in this system, because otherwise the number of lanes and the systems that use them don’t stack up.To be clear, it’s not like the NAS is massively over-subscribed on PCI bandwidth, but if you fill every port and slot, something is going to give at some point.There is also something of an oddity with the memory model of this NAS. If you head over to Intel and look at the specifications for the N350, you might notice that Intel states the maximum amount of memory this processor supports is 16GB. Well, that appears to be wrong, because you can put 32GB in this NAS, and it will work. You can’t add any more, and because it has only a single memory channel and SODIMM slot, you can’t use two 16GB modules.If you want more memory, you need to take the next rung up on the processor ladder. The Ugreen NASync DXP4800 Pro uses an Intel Core i3-1315U, and that has dual-channel memory enabling it to address 96GB.(Image credit: Mark Pickavance)Dual 5GbE is one of the most consequential hardware changes over the F4-424 Pro. With link aggregation configured on a managed switch, the aggregate theoretical bandwidth reaches 10Gbps. Single-client throughput sits at up to 625MB/s per port, compared to 312MB/s from the F4-424 Pro's 2.5GbE ports. For 4K video workflows, large file transfers, and multi-user small office environments, that improvement is tangible.However, it begs the question of why they didn’t simply combine the bandwidth and offer a single 10GbE port in the first place? If anyone wants another 2.5GbE line, perhaps for a network failover option, USB adapters that can use the 10Gbps USB-A ports are inexpensive.The absence of a 10GbE port will disappoint buyers who want the maximum headline figure. The Ugreen DXP4800 Pro provides single-port 10GbE at $719.99, and the DXP4800 GT provides dual 10GbE at $559.99. TerraMaster is positioning 5GbE as a practical middle ground that delivers meaningful real-world improvement without requiring expensive 10GbE switching infrastructure. That argument has merit for some buyers, although 5GbE network switches that support channel-bonding aren’t especially common.From a hardware perspective, the new N350 isn’t a huge move from the N305 used on the previous generation. What’s different here is that this hardware is better at managing power, heat, and the limited PCIe lanes available to it.In a straight compute fight, the N305 might be better, but for running 24/7 through a hot summer, the N350 has some advantages that it might need.Features: 4 / 5TerraMaster F4-425 Pro: Software(Image credit: Mark Pickavance)TOS 7OpenClaw AISubscription appsTOS 7 is what TerraMaster is staking the F4-425 Pro's reputation on. Earlier TOS releases were functional but acknowledged as trailing Synology DSM and QNAP QTS in polish and app ecosystem depth. TOS 7 does not try to close that gap incrementally. Instead, TerraMaster has chosen to reframe the competition around an AI-first workflow that neither Synology nor QNAP currently matches.The OpenClaw assistant is the visible centrepiece. A single click from the app centre installs it, after which the user can issue natural language commands for the full range of administrative tasks: RAID configuration, user account management, backup scheduling, security setup, and file management. The theory is compelling. A buyer who understands that they need a NAS but has never configured one could set up a working system through conversation.Except there is a huge hole in this plan, since the buyer needs to understand how to install and configure OpenClaw, use LLMs and their API keys. And, those require you to fund your API of choice to accept those messages from OpenClaw, unless you have the expertise to run your own local models using Ollama, and direct OpenClaw to use that.If you are willing to use AI but not pay for it, the fun doesn’t typically get started.I tried my best to get the OpenClaw beta to run on this hardware during one of the hottest afternoons of the year, but failed miserably. I got Ollama installed as a Docker container and even loaded a model to use for local access, but I couldn’t get OpenClaw to work with it. Maybe on a cooler day, with better documentation, I could manage this, but given the level of personal experience I brought to this problem, it isn’t something anyone new to AI would want to embrace.NAS manufacturers have a history of ambitious AI and automation claims that perform well in demonstration scenarios and inconsistently in everyday use. TOS 7 has been in development for over 300 days, according to TerraMaster, but that development timeline says nothing about robustness across edge cases, network configurations, and drive combinations that real users will bring to the table.And having a tool like OpenClaw running on the NAS, with the ability to create users, shares, and folder structures, and to delete things, might not be as wonderful as it first seems.(Image credit: Mark Pickavance)Ignoring TerraMaster's attempt to board the AI hype-train, the foundation platform for TOS 7 is solid. Docker and virtual machine support carry forward from TOS 6. The backup suite is comprehensive. Plex and Emby are available from the app centre. DLNA compliance means out-of-the-box compatibility with smart TVs and media players without any configuration. HyperLock WORM protection addresses compliance requirements for business users. The security baseline, including AES folder encryption, OTP authentication, and the firewall, is mature.Where TOS has historically needed work is in surveillance capabilities and app ecosystem depth. Whether TOS 7 addresses the Surveillance Manager's lack of a dedicated client with timeline and event marking is a specific testing priority.There isn’t any debate, this is the best version of TOS yet, and it still has a few features that other NAS brands still haven’t delivered. One I especially like is the TRAID hybrid array model, which allows mixing drives of different sizes and yields more resilient capacity.Only Synology offers anything comparable, and users of QNAP, Asustor, and Ugreen would gladly welcome such a feature.A feature that none of those brands might embrace is that the HDMI port on this machine is effectively unused. It’s been a decade since TerraMaster first launched a NAS with an HDMI port on it, and in my review of that equipment, I commented that the port needed support by first-party apps for media playback. Ten years on, the HDMI port remains useful for TerraMaster production staff to check whether the systems are booting correctly, but is of almost zero use to their customers. Everyone else integrates their HDMI if they have it, but TerraMaster stubbornly refuses to. There are some nefarious ways to get the HDMI to work using Virtual Machines, but that this annoyance was left to fester for so long is incredibly poor.The other issue that TOS 7 doesn’t address is TerraMaster's somewhat confused approach to the first- and third-party application ecosystem.Software: 4 / 5TerraMaster F4-425 Pro: PerformanceEfficient systemBalancing speeds(Image credit: Mark Pickavance)When a NAS has four SATA bays, it effectively constrains its peak transfer performance to or from that array. Even with the fastest possible option, RAID 0 on four drives, with each NAS drive being like the WD Red Plus models I used for testing, the total array is only capable of four times the 199MB/s limit for those drives. That’s 796MB/s. which wouldn’t saturate a single 10GbE LAN port, if the F4-425 Pro had one.More realistically, the RAID mode of choice is likely to be one with redundancy, reducing performance to 597MB/s, which fits rather neatly with what I’d expect from a 5GbE transfer.But this NAS has two LAN ports, and without any enhancements, using channel bonding of the two 5GbE ports is unlikely to help the total amount of data read or written.The only way to make things run faster would be either to use SATA SSDs, or NVMe storage, or use the M.2 for caching. I used the latter and was able to get more throughput.One interesting bit about the M.2 slots and using them for caching on this system is that, typically, for read and write caching, two SSDs are required. But not on TOS 7, which will allow you to use a single SSD for both read and write caches. If you are wondering why others haven’t followed TerraMaster’s example, when you choose to do that on this NAS, you get plenty of warnings about how this can go wrong.I tested a Crucial P5 500GB, and it achieved an NAS score of 859 MB/s. Therefore, to saturate both 5GbE LAN ports would probably require two NVMe drives in a RAID 0 configuration.The lesson here is that even with all your storage ducks in a row, it might prove challenging to deliver sufficient performance for the dual 5GbE LAN ports unless you use caching liberally.Performance: 4/5(Image credit: Mark Pickavance)TerraMaster F4-425 Pro: Final verdictMy views on the F4-425 Pro are a little mixed. It’s easy to get distracted by the all-singing and dancing TOS 7, and gloss over some of the obvious misplays. What I liked most was how efficient this platform can be, something that often gets overlooked when talking about machines that can run for months or years without ever stopping.But the yin to that yang is that there isn’t a huge amount of power to throw at Docker containers or AI, and that’s where many brands are taking their devices.I’m also confused why this machine ended up with two 5GbE LAN ports when its competitors are delivering 10GbE. The internal M.2 slots and the four SATA drives are all geared towards supporting a single 1GB/s data flow, so why would you split it into two?And, for the billionth time of asking, where are the drive tray locks, the apps that can output via HDMI, and better ports than USB 3.2? After ten years of NAS development, two of these questions are long overdue for an answer.Don’t get me wrong, there are good things here for those who don’t need computational power on the NAS and like cool running, but it feels like TerraMaster is trying to put off the evil day when its next NAS will need to deliver hardware with a wider appeal than the F4-425 Pro.(Image credit: Mark Pickavance)Should you buy a TerraMaster F4-425 Pro?ValueNot a great spec considering the price3.5 / 5DesignOld enclosure, and no bay locks or numbers4 / 5FeaturesThre M.2 slots and dual 5GbE LAN4 / 5SoftwareTOS 7 is mostly great4 / 5PerformanceConstrainted by Gen3x1 M.2 slots and 5GbE LAN ports4 / 5OverallAN efficient four-bay, but hardly excisting4 / 5Buy it if...You want something flexibleFour drive bays have enough capacity to hold plenty of data, and the dual 5GbE LAN ports can distribute it effectively. And, potentially, it could be used to run an AI Agent.You want minimal power consumptionThe CPU in this NAS is nearly as power frugal as an ARM processor, but can still run X86 code.Those looking for a small four-bay NAS that can stay cool when the going gets hot should take a closer look.Don't buy it if...You want ThunderboltThunderbolt and USB4 ports enable connecting fast external SSDs or HDDs to add even more storage. If you want Thunderbolt ports or PCIe expansion, then the F4-235 Pro isn’t for you, as it only has USB 3.2.You need TOPSThose working on local LLMs often need TOPS, or Tera Operations per Second. And, depending on the processor, and if it has an NPU (neural processing unit), the performance for AI is often rated in TOPS. The N350 is rated at only 2 TOPs, which is way below what the latest Intel and AMD mobile processors offer. They often achieve over 100 TOPS. View DealFor more storage solutions we've tested the best NAS hard drives around