Introduction

I would like to thank Synology for supplying the review sample.


After the DS1621+, Synology's first Ryzen-based NAS which I reviewed a while ago, it was time to evaluate an Intel-powered NAS. The DS1520+ is equipped with a quad-core Intel Celeron J4125 clocked at 2 GHz under normal conditions and at 2.7 GHz when things get tough. It is also equipped with 8 GB of DDR4 non-ECC RAM, which is enough given its operating system is not resource hungry. Besides the five bays for drives, it also has two M.2 drives slots for NVMe drives, typically used as cache storage. If five drive bays are not enough, you can connect a couple of DX517 expansion units and increase this number to 15! Note that these DX517 units are not cheap at around $600. Still, it is nice to have the option to upgrade the server's storage instead of having to move to another server or NAS.

The DS1520+ is not for the average user, who would usually pick a two-bay NAS to keep the expenditure as low as possible. This NAS is ideal for small offices, or larger ones with the addition of an expansion unit. It is also suitable for enthusiast users wanting high network transfer speeds and loads of storage space. The only problem is that it doesn't support an optional 10 GbE network card because it lacks a free PCIe port. That having been said, the slightly more expensive DS1621+ can take such a card, so if you have a 10 GbE switch or plan to upgrade soon, you had better keep this limitation in mind. The four Gigabit Ethernet ports of the DS1520+ can be combined for up to 400 Mbit speeds, which is still not as fast as 10 GbE, and you will have to use four Ethernet cables to connect the NAS to a switch that supports Link Aggregation. Another downside compared to the DS1621+, which costs $100 more, is that the DS1621+ uses an internal power supply while the DS1520+ is powered through an external adapter. Internal PSUs offer better performance, more power, and are more reliable since they have lower operating temperatures. Power adapters, on the other hand, are easier to replace if something goes wrong.

Specifications

This is not a budget-centric NAS. It mainly addresses small office environments and enthusiast users with an increased budget for their home server. A three-year warranty has been included, and around an additional $100 will get you their EW201 bundle, which extends it to five years.

Contents and Bundle

There are no surprises here. A plain cardboard box holds this Synology NAS. There is a colored sticker to break up the monotony, with a photo of the product and a brief description of its features. Finally, the box has a top handle, which comes in handy.


As expected for a product of this price point, packing protection is excellent. This bundle includes a quick installation guide, two Ethernet cables, screws, plastic keys for the disk trays, and a power cable. Given the four Ethernet ports this NAS has, I expected more Ethernet cables.
The five drive bays take up most of the space at the face of the NAS.


The LED indicators at the face of the NAS are for Drive Usage, Status, and Alert. The power button and front USB 3.0 port are below these.


The Synology logo punched into the side also acts as an exhaust grille.


You will find the access door to the M.2 slots on the bottom, along with the power specifications sticker and another sticker providing instructions on how to install the NVMe drives.


The cooling fans, most I/O ports, and the DC input socket are at the back.


The eSATA, USB 3.0, and all four Ethernet ports.


A scheme of the NAS, provided by Synology, depicting all points of interest.


A look at the NAS with its trays removed.


There are no vibration damping pads, which may increase HDD noise. The installation of 3.5" disks is tool-less, but this is not the case for 2.5" disks, like those I used.


The power adapter's model number is EA11011H-1200. It can deliver up to 120 W with 12 V output. It is made by EDAC Power Electronics, a Taiwanese company.

A Look Inside

Taking this NAS apart is not so easy. I had to deal with lots of screws, and you need to apply some force to remove the plastic cover.


The main body is made out of metal, while the enclosure is made out of plastic. The server consists of three PCBs, the main one and two PCIe cards. The mainboard has many similarities with the mainboard of the DS920+ since both servers use the same CPU.


The mainboard is small, and a heatsink covers the SoC. There is no active cooling for the latter.


There are three VRMs close to the CPU socket area. Two of these most likely power the CPU, and the third handles the system memory. Mostly, solid tantalum surface mount caps are used for filtering and energy storage. Power management is handled by a Richtek RT5077A.


Two AP4435GM FETs are installed right next to an SK34C schottky barrier diode (SBR).


On the other side of the mainboard, we have the PCIe ports, USB 3.0 header, and RAM, which is soldered to the mainboard,


The single RAM slot is occupied by a 4 GB DDR4 2666 MHz SODIMM.


The mainboard's BIOS chip is a Winbond 25Q128FWSQ. There is also a Macronix MX30LF1G18AC-TI 1 Gbit NAND flash memory chip on board, and its controller is a Phison PS2251-68.


The PCIe card that hosts all four Ethernet ports can also take up to two M.2 drives. On it, I found a PCIe clock buffer IC (ICS 9BD403DGLF), Winbond 25X20CLNIG flash memory chip, and four Realtek RTL8111HS Gigabit Ethernet controllers.


The SATA controllers are by Marvell, and their model numbers are 88SE9235 and 88SE9170.


The SATA expansion card can host up to five drives.


A PCIe bridge controller by ASMedia.


An 8-bit microcontroller by PIC—its model number is PIC16F18345. It most likely handles the server's LED indicators.


Next to the buzzer are a coil (marked R47), two solid tantalum caps, a bunch of MLCC caps, and a Vishay SiC632 integrated power stage.


An Altera complex programmable logic device (CPLD).


A 4410 MOSFET is installed right below a Vishay tantalum cap.


The rear side I/O ports of the mainboard.


Y.S. Tech provides the two 92 mm diameter fans. Their model number is FD129225LL-N (12 V, 0.12 A, 1900 RPM, and 36.3 CFM). According to Y.S Tech, these fans use Sintetico bearings, which look to be of high quality and will easily outlive any plain sleeve bearing.