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Most chassis on the market today have plenty of internal mountings for 3.5" hard drives, but if additional mounts are needed, or the drives need to be easily accessible, a hot swap rack may be necessary. Hard drive racks that mount in a 5.25" bay are one solution to both of these problems. You can fit as many as three 3.5" hard drives in the space of two 5.25" bays, so many chassis on the today's market can have as many as six additional 3.5" drives installed.
These racks often feature hot swap capability, meaning that the hard drives can be easily removed or replaced without having to open up the chassis. This is especially useful for servers where any failed drive needs to be replaced quickly and if possible done with the machine still running. Note that while many modern motherboards support hot swapping of hard drives, we still strongly encourage the practice of shutting off the system before removing/replacing a hard drive.
Today we will be reviewing three different 3.5" hot swap racks from Kingwin. They allow for the mounting of one, three and four hard drives respectively.
With hard drive enclosures (whether they be hot swap or not), there are three major factors to consider. The first is how the rack mounts. We've seen some cases where a hard drive rack is so long that it can damage capacitors or cables connected to the motherboard. Needless to say, that is not a good thing. Many cases now also have short tabs below each 5.25" bay to assist in drive mounting that can cause problems with the large, single piece hard drive racks. If the manufacture did not account for these tabs and take the necessary design precautions, the rack would simply not be mountable without chassis modification.
The second factor is cooling. Even if the rack is dead silent due to having a very quiet fan, it is not all that useful if the drives inside overheat. It is always a challenge to balance both noise and cooling in a system; as depending on the purpose of the system, one or the other may be more important.
The third and final factor is the amount of noise the rack contributes to the system. Many single drive racks do not have fans so noise is not an issue on those, but some larger racks use fans as large as 120mm. While hard drive racks are most often used in server environments, there are some instances where the system it is in is relatively close to the user; so overly loud fans may be a factor in choosing a hard drive rack.
We will be using two different cases to check the rack mounting. The first is the Antec P183 V3 which uses rails to mount 5.25" drives. The second is the LanCool PC-K7B which has tabs below each 5.25" bay to assist in drive mounting.
To test the cooling of each enclosure, we filled them with Western Digital Black 1TB SATA 6GB/s hard drives which run relatively hot. To give us a baseline comparison, we also ran a set of testing with the hard drives not in any enclosure to see how the temperatures compared to if the drives were not installed in a rack. The KF-1000-BK does not have any active cooling, we did not perform any cooling testing on it.
Since quieter operation might be desirable for some users, we also performed the same set of tests with the stock fan replaced with a quieter model. For the KF-4001-BK we used an 120mm Scythe Slip Stream 800RPM fan. For the KF-3001-BK we used an 80mm Antec Tri-cool on low.
To load the drives, we configured them into a single RAID 0 (stripe) and continuously copied/deleted data until the temperatures stabilized. Temperatures were taken directly from the SMART data of the hottest drive using SpeedFan.
|Idle – Stock fan||38° C||34° C||33° C|
|Load – Stock fan||40° C||35° C||34° C|
|Idle – Replacement fan||–||37° C||37° C|
|Load – Replacement fan||–||40° C||40° C|
Comparing the two racks to each other, it is clear that neither rack really has an advantage in terms of cooling. The single degree difference with the stock fan can easily be attributed to normal testing variations. While replacing the stock fans with quieter versions does increase temperatures on both racks by 4-5° C, they are still below any danger levels. 40° C is however warm enough that we would recommend not replacing the fans if the system is going into a hot environment (like a house without air conditioning).
To put it bluntly, both the KF-3001-BK and the KF-4001-BK are very loud. We usually like to compare the noise levels of components to some of our most common case fans, but both of these coolers are louder than even our loudest case fan: an Antec Tri-cool 120mm fan on high. Interestingly, if the fans are removed from the racks, they are closer in noise to an Antec Tri-cool on medium. So the internal components in these racks (mainly the PCB board and the hard drives themselves) cause such a restriction to the airflow that it creates a lot of "airflow noise".
Luckily, our cooling tests showed that you can replace these loud fans with quieter versions and still adequately cool the hard drives. One thing we noticed is that while the quieter fans did get a little louder when mounted onto the racks, they did not have nearly the same jump in noise level that the stock fans did. This is due to the fact that the quieter fans move much less air, so you don't get the same amount of airflow noise. To exaggerate the effect, it's like difference in sound when you are walking versus when you stick your head out a car window driving at 60mph.
In server environments where noise is not a concern, the stock fans will be just fine. If the system is within hearing distance of the user and is in a cool enough environment however, it may be worthwhile to replace the stock fan with something quieter.
We have a long history of mounting conflicts with larger hard drive racks, so we were very pleased that these racks mounted without serious problems in both of our test chassis. While this does not guarantee that they will work in every chassis, it is definitely a good sign. The KF-1000-BK is the only one that had any issues, and that was due to the fact that drive rails need a rigid surface to mount to. Because of the rubber grommets, the KF-1000-BK does not have a rigid enough surface to guarantee solid mounting.
From a cooling perspective, all of the racks we looked at performed just fine. The two racks with fans were much louder than we would normally like, but as the stock fans are just standard 3-pin fans, it is relatively easy to swap them out with quieter fans. We would suggest not replacing the fans unless the system is going into a nice cool environment to avoid potential heat issues however.
One thing we do not like is the fact that the KF-1000-BK does not have any enclosure and is completely open. While it may seem like overkill to have a single drive rack fully enclosed, the possible annoyances due to the open nature of the rack can be very frustrating. Imagine that a fan or power cable somehow managed to drop in through the top of the rack while the drive was removed. You may be able to reach in through the rack and move it out of the way, but likely you would have to open the chassis up to move the wire to a more secure location.
Overall, if you are in need of additional 3.5" hard drive mounts, or need hot swap capability, any of these racks would make a great choice.