ICY DOCK FlexCage MB975SP-B Review Tray-less 5-in-3 Hot Swap


The ICY DOCK FlexCage MB975SP-B is a hot swap tray-less backplane that brings significant flexibility to the system. Hot swap SATA backplanes such as the ICY DOCK FlexCage MB975SP-B are very common to make swapping hard drives in and out easy on a user. They are especially easy for tasks such as swapping drives in to image, backup drives and etc. Most of these devices require one to secure drives into a drive tray (or caddy / sled) prior to inserting a drive in the enclosure. Tray-less designs like that of the ICY DOCK FlexCage MB975SP-B allow users to simply insert a bare hard drive. Overall swap times take a minute or two less. For anyone that has managed many disks in traditional hot swap sleds, having to screw in/ out drives takes quite a bit of time.

Test Configuration

For this test we will use our recent AMD workstation platform as we have been using with many of our previous reviews.

  1. CPU: AMD FX-8350
  2. Motherboard: ASUS M5A99FX Pro R2.0
  3. Memory: 32GB 4x Kingston 8GB
  4. GPU: XFX ATI Radeon 7950 3GB
  5. OS Drive: OCZ Vertex 4 256GB
  6. Enclosure: Norco RPC-470
  7. Hot-swap chassis: ICY DOCK FlexCage MB975SP-B
  8. Hard drives: 5x 3TB Seagate 7,200 RPM drives (ST3000DM001), 3x 3TB Western Digital Red Drives (WD30EFRX)
  9. Power Supply: Corsair AX750 750w 80Plus Gold PSU
  10. OS: Windows 8 Pro 64-bit, Ubuntu 12.04 Server

Overall a fairly standard configuration for custom-storage applications.

The ICY DOCK FlexCage MB975SP-B

Looking at the front of the ICY DOCK FlexCage MB975SP-B one can see a few unique features. There are individual drive switches that allow a user to power on or off each drive individually. This is a great feature for users looking to make “cold” backups. One can power down drives when not in use.

ICY DOCK FlexCage MB975SP-B Front Closed
ICY DOCK FlexCage MB975SP-B Front Closed

The latches do not have locks on them. They do have a fairly secure locking mechanism. Inside the recessed middle portion of each front door, there is a latch that must be depressed to open. Since there is clear separation between each drive, it is difficult to accidentally engage the wrong release. This is very important because each drive is spring loaded so opening the door immediately ejects drives. For swapping quickly, this is great. One just needs to ensure that they are not inadvertently ejecting the wrong disk.

ICY DOCK FlexCage MB975SP-B Interior
ICY DOCK FlexCage MB975SP-B Interior

The rear of the unit is certainly interesting. There are five 7-pin SATA connectors, one for each drive. Power is handled through three SATA power connectors to the rear of the unit. Like most hot-swap cages, ICY DOCK includes a rear fan. The differentiator here is that ICY DOCK gives quite a bit of customization flexibility with the unit. We see both a removable fan that uses standard phillips head screws. The replacement fan has both 2-pin and 3-pin fan headers. Couple this with a fan speed control unit and it allows for a user to customize the thermal performance and acoustics to a large degree.

ICY DOCK FlexCage MB975SP-B Rear
ICY DOCK FlexCage MB975SP-B Rear

Generally we get two questions in terms of performance of these units. The first is whether the data performance degrades using the backplane in the hot-swap cage.  We test this with every unit and with this one, the performance differences were under 0.5% when we averaged test runs. Close enough to be within our testing margin of error. We use both our fast Seagate drives and our slower Western Digital drives for this test but the results were similar.

The second question is regarding thermal performance. In terms of thermal performance, the Icy Dock MB973SP-2B fared well in our testing. Even under load, the Icy Dock MB973SP-2B performed well with 7,200rpm drives.

ICY DOCK FlexCage MB975SP-B Temperatures
ICY DOCK FlexCage MB975SP-B Temperatures

These temperatures are fairly good for a 5-in-3 unit where there is less room for airflow than a 4-in-3.


Overall, through our battery of tests the ICY DOCK FlexCage MB975SP-B performed very well. Data speeds were not decreased when we used the cage. Likewise, thermals were kept under control. ICY DOCK does focus on solid construction here and most of the unit is made of metal giving it a sturdy feeling. The plastic on the review unit we were sent seems very solidly built and not flimsy. One major advantage to the ICY DOCK unit is the fact that the fan can be customized to optimize for thermal or acoustic performance. For many workstation applications, this is a prime consideration. The tray-less design makes swapping drives much easier as there are no small screws to deal with. Having individual power on/off switches makes the swapping process even easier. The ICY DOCK FlexCage MB975SP-B costs about $125 but that is in the going range for this type of device. As a package, this is a unit that performs well for workstations that need easy hot-swap features.

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Patrick has been running STH since 2009 and covers a wide variety of SME, SMB, and SOHO IT topics. Patrick is a consultant in the technology industry and has worked with numerous large hardware and storage vendors in the Silicon Valley. The goal of STH is simply to help users find some information about server, storage and networking, building blocks. If you have any helpful information please feel free to post on the forums.


  1. I wish someone made a design with tool less trays instead of tray less cages. I can never tell which one I want.

    I think over $100 for this type of device is almost too much. You can get a mid-tower case with power supply and motherboard combo for under $100. I fail to see how the logic board in this ICY Dock is more complex. I also fail to see how the chassis is more costly to build and ship to the US than a mid-tower case.

    I hope one day some company figures out to sell this type of device for $60. Would sell like cronuts in NYC

  2. I don’t mind the look of the unit but have concerns on the lack of vent holes through the rear back-plane.


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