Speaking of the fan, in a quiet room, the fan noise is audible. But I don’t consider it as loud or obnoxious. Some people may consider this as “noisy”, especially if they are used to very silent conditions. However, in my years of using a PC and testing several components with fans, like graphics cards or CPU coolers, the DF4RU3 isn’t the loudest I heard. Important Note 1】The enclosure will enter into sleep after 10min of data inactivity-the function can be adjusted/cancelled. Use our firmware or the third-party software, like Amphetamine/KeepAliveHD/Prevent Disk Sleep (You can set it to write to your drive a 1kb noted file every 5 minutes. The device will no longer enter sleep mode.) . Like I mentioned earlier since I use the DF4RU3 in normal mode only, I didn’t have much further need of the software other than to update the firmware. But if you plan to use this external hard drive enclosure for RAID, you can use the software. With this enclosure the output of the command ls /dev/disks/by-id corresponded to “serial number of the case.DISK1” and commands like udevadm could only see the data of the enclosure instead of the data of the drives.

I guess if one was planning to use the drives normally, having four connected via a single USB cable would affect performance compared to connecting each one to a separate USB port but I'd connect the drives to my PC whilst I'm filling them with plots and then once in the enclosure and connected to the RPi, they'd just be sitting there waiting to be read if any plots pass the filter. With some of the drives, I might need to add some plots later over the LAN but if I copy them as each one completes it shouldn't be too onerous and I'd only be writing to one drive at a time still.

Above, you can see the front and front-side view of the DF4RU3. It looks stylish and has a nice aesthetic. The design reminds me of Apple’s Power Mac G5 desktop PC. It is mostly metal on the outside making it very sturdy and robust. Whereas, its sides are covered with a clear acrylic side panel.

Other than the nice (RGB) lighting of the fan, there is (really) nothing to see from the inside. You can partially see the power supply area, and the Blue LED indicator for each drive bay. Nevertheless, the transparent side panels do look nice overall. Just be careful not to scratch it since it is not scratch resistant. Yottamaster RAID Manager Software

Each tray is made of a combination of metal and plastic. The frame itself is solid metal, whereas the sides and the front portion is plastic. The pull tab is plastic covered with perforated metal. I guess this is to give the pull tab more rigidity. However, the joints of the pull tab and the whole mechanism (except for the spring) are plastic. So, it’s best not to yank the tray with excessive force. I did not disassemble my unit since I do not want to damage it unintentionally. Here’s a peek of what’s inside the DF4RU3 from the drive bay’s view. You can see the SATA power and data ports from this angle. I don’t see any vibration dampening on the tray or inside the drive bays. But vibration coming from the hard drives doesn’t seem to be an issue.

According to Yottamaster, this is their first attempt to include an RGB fan in their product. Due to the limitations of the PCB design, they can not add additional features or controls for the RGB fan. The fan is just for aesthetics since they are marketing this external enclosure to gamers, streamers, and content creators.

Finally, I tested the drives using CrystalDiskMark, and this time random workloads are included. The results are similar to the other two tests above. The Samsung 870 QVO SSD performs best when connected to the motherboard due to the speed limitation of the DF4RU3. But it doesn’t affect much for hard disk drives since they are both slower than the SSD. Each device needs to be connected to an AC power supply separately. "Main" port refers to the main data transfer port and "HUB" port is the serial port. At the time of writing this review, the DF4RU3 can support up to 64TB of storage capacity. That’s 16TB each drive bay. Currently, the Seagate IronWorlf Pro, Seagate Exos X16, and WD Red PRO are some of the drives that have 16TB capacities. And they are also available in 18TB capacity. Although, I am not sure if Yottamaster will release a firmware in the (near) future that would enable the DF4RU3 to support 18TB hard drives or 72TB in total. Since the DF4RU3 has a USB 3.0 interface and is limited to 5Gbps of theoretical speed; I have more or less a rough idea of how this external enclosure will perform. I tested the DF4RU3 with a WD Red 12TB HDD and a WD Red PRO 14TB HDD. Also, I tested it with a Samsung 870 QVO SSD to see how much performance are we going to lose if we use a much faster drive. Also notice that there is a bit of performance drop. Just a tiny bit, by a few megabytes per second. I doubt that it will be noticeable at all in real-world use. Okay, time to wrap up this review. Pricing and Availability