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MB998SP-B: It's 8-way bay day!

A Review On: Icy Dock ToughArmor MB998SP-B

Icy Dock ToughArmor MB998SP-B

Rated # 1 in HDD Accessories
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Price paid: $128.00
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Pros: 8-drives in 5.25" bay? Yes, please! All-metal design feels incredibly solid

Cons: Drive caddies can be challenging to line up into the cage, pricey premium product


IcyDock has a wide lineup of hard drive accessories from the enthusiast-level ExpressCage series to the enterprise-oriented ToughArmor series. I’ve been reviewing the latter for years now and have been able to see the lineup mature from only a few units to a whole host of sizes and capacities.

Today I have two units for review: the new flagship MB998SP-B (http://www.icydock.com/goods.php?id=192) and an entry into the external storage accessories with the MB991U3-1SB (http://www.icydock.com/goods.php?id=188).

Device Overview and First Impressions

IcyDock’s external 2.5” USB3.0 solution targets the portable drive market. While it’s certainly larger and heavier than Vantec and Rosewill enclosures, it doesn’t require an external power source like the IcyDock Blizzard 3.5” drive enclosure. It also sports a Kensington lock slot if you're worried about the enclosure walking off, which is nice.

Unlike super-svelte external drives, though, the MB991U3 sports a removable drive cage that’s compatible with any other MB991TRAY, MB992TRAY, MB998TRAY (in the MB998SP-B below), or MB994TK-B. This makes swapping drives between your main machine and the enclosure a quick and painless experience if you already own a 5.25” bay device using these caddy types.

Check out the video below showing cross-compatibility between the MB991U3 enclosure and the MB998TRAY:

Back in 2012 when I first started reviewing IcyDock’s ToughArmor lineup, the MB994SP-1 was the big dog -- sporting a total of four 2.5” devices in a single 5.25” slot. However, in 2013 IcyDock launched an even beefier 6-unit model the MB996SP-6SB. And now we have the MB998SP-B to take the crown once again.

The removable drive trays are thinner than the MB996 and won’t likely fit prior models. To get so many drives in such limited space, the unit also limits compatibility to 7mm HDD/SSDs. However, the caddies for each drive still support an activity/power LED and feature full-metal construction.

Key Features
  • Full metal construction for durability and drive protection.
  • Removable EZ-Slide Mini tray supports hot-swap function.
  • Supports 2.5” SATA III hard drive / SSD with 5mm, 7mm, 9.5mm & 15mm height.
  • USB 3.0 interface supports UASP
  • Universal drive slot that is compatible with wide range of ToughArmor drive tray includes MB991TRAY, MB992TRAY, MB998TRAY (in the MB998SP-B below), or MB994TK-B
  • Eagle-hook lock system & 2-segment safeguard key lock keeps drives secure within the enclosure.
  • Multi-Flow Technology (MFT) - provides excellent passive cooling.
  • Anti-Vibration Technology (AVT) - creates a safe environment for hard drives or SSDs.
  • Active Power Technology – Device only power up if there are drive installed.
  • USB 3.0 with UASP support and backward compatible with USB 2.0 interface.
  • USB bus-powered, no power adapter is required.
  • Removable tray system for easy maintenance.
  • Compatible with wireless router / DVR / Smart TV / Android TV box via USB interface.
  • Anti-slip rubber protective sleeves enhances enclosure stability and reduces shock impacts.
  • ICY DOCK 3 year warranty.

  • Heavy duty full metal construction with commercially designed for Medical & Military systems, Media servers, and IPCs, approved & used by Tier 1 companies
  • Perfect for rugged applications and complies to flammability requirements
  • Fits 8 x 7mm 2.5” SATA hard drives or SSD’s in a single 5.25” bay for high performance RAID applications
  • Dual 40mm fans keep your drives from overheating
  • Requires only 2 x 15pin power connectors to power all 8 bays
  • Drive label plugs to keep track of your RAID drives
  • Anti-Vibration Technology (AVT) - creates a safe environment for hard drives or SSDs
  • Active Power Technology (APT) - individual led & cooling fan only powers up if there is a drive installed in the bay
  • Eagle-hook lock system keeps drives secured within the enclosure
  • Removable tray system for easy maintenance
  • Supports SATA 6Gbps and hot swap
  • Supports SATA and SATA power cables with locking latch design
  • Industry leading 3 year warranty with exceptional customer support

Construction and Aesthetic

Keeping in line with the prior ToughArmor devices, both the cage and caddies are full metal (see: steel) construction. IcyDock is obviously targeting enterprise or OEM customers. In the gaming marketplace, where wild colors and gimmicky plastic designs are the norm, the ToughArmor design is quite muted. Whether the design is a positive or negative is purely a personal preference, but the all-metal design is certainly an upgrade over the majority of other offerings on the market.

Both devices feature matte black powder coating without and within. Even the inside of the cage itself is powder coated. The only exception is a small swatch of paint masked on the inside of the unit for EMI grounding of the drives, which is a nice detail.

The caddies have a black grill facade that’s identically powder coated but the mounting plate and anti-vibration hardware is left in a stock steel or aluminum finish, respectively.

The MB991U3 uses small vents cut within the housing for airflow, whereas the MB998SP uses dual 40mm fans for ventilation. Unlike the MB994 I reviewed some time ago, there is no switch to disable the fans. However, IcyDock did respond by saying that the fans could be unhooked and the bay device would work just fine without them. More interesting yet, they said they the fan headers would work with your own fans as long as they’re 12V (and likely don’t draw much more power than the 40mm stock fans).

Here's my few gripes about the two units:
  • I wish the MB991U3 had the same anti-dust flap that the MB991SK-B (http://www.icydock.com/goods.php?id=162) does.
  • With the MB998SP, lack of a fan switch means you’re either stuck with the high-pitched whine of small 40mm fans, or you’re hackishly unhooking them entirely.
  • Also, with the MB998SP, I felt the drive caddies didn't stay lined up with the enclosure very well without a drive installed. This means that I bent a few of the sleds inserting them until I got the hang of it. The sleds are also flimsier than the MB991's larger caddy. But you have to cram 8 of them into the bay, so I understand the space limitations were the primary factor for this.

In either case, they’re pretty minor gripes and don’t really impact performance.

Test Equipment:

  • Seagate Momentus XT (500GB HDD)
  • SanDisk Ultra (120GB SSD)
  • Late-2013 Macbook Pro (256GB Samsung PCIe SSD)
  • Asus Rampage II Gene Motherboard (SATAII)
  • Laser Temperature Reader
  • Black Magic Disk Speed Test (OSX)
  • HD Tune Pro 5.60



The performance of the MB991U3 was fully in line with my expectations. When coupled with an SSD, it pushed the USB 3.0 limits pretty far based on other benchmarks I’ve seen. When installed with a conventional HDD, the numbers are certainly limited by the speed of the drive. In short, it’s going to be the USB 3.0 interface and type of drive that imposes the limits on your performance, not the enclosure.


With the MB991U3 attached to my Synology NAS, the enclosure stabilized with a temperature of 26.9C. Even after completing backups, it didn’t move beyond 28C. This performance is more than adequate but I doubt the all-metal construction offers all that much in the way to improved thermals, given the enclosure doesn’t have significant metal-to-metal contact with the drive other than the mounting plate of the caddy itself. If you’re concerned about drive heat your best bet is simply to use an SSD instead of spinning rust drives.

Rather than concern myself with an absolute performance test, which would be impossible with my aging SATAII platform, my goal with the HD Tune Pro benchmark is merely to illustrate that the MB998SP yields the same performance as my existing setup.

With the MB998SP installed, I had a transfer rate between 222MB/s and 224.6 MB/s, which is identical to the performance with the drive directly installed to the SATA headers. As I expected, there was no performance degradation, even with the extra bit of hardware between the SSD and my motherboard.

Conclusion, Pricing and Availability

Overall, these two devices met all my performance expectations that I’ve come to have with Icy Dock products. The ToughArmor series is designed around the enterprise and OEM market, and its build quality and feature set reflect that. Where it’s also reflected is the price.
Neither of these items are particularly budget-focused. In the competitive 2.5” enclosure space, you can get plastic USB enclosures for less than $20USD. At over 3 times that price on Newegg, it may give some potential buyers pause. But if you’ve already bought into the ToughArmor product line, this enclosure makes a lot of sense. It’s durable, cross-compatible, and meets a host of industry requirements that average users may not need.

With respect to the MB998SP, you’re going to need some beefy hardware already to make use of eight drives in the first place. Not every motherboard has 8 headers to work with. But, hey, if you’re trying to get 9GB/s throughput for 8K video editing, it seems like this may be a good way to make that happen (http://icydock.com/knowledge.php?id=56).

Overclock.net has rarely been a place that gets too hung up on price alone. There are some people who simply want the features and performance, regardless of price. That was the case for me when I was looking into the MB994SP-3SB. I've been happy with it for years and suspect you could pick up either of these items and you're more likely to outlive the interface (SATAIII and USB3.0, in this case) than the units themselves. I’d recommend these items as for anyone who's looking for a high quality enclosure for their rig or to supplement an existing ToughArmor solution with an external enclosure.

  • Durable all-metal design means these devices are going to last a long time
  • Cross-compatibility between IcyDock designs makes for compelling solution between multiple machines
  • (MB998SP)Performance is on-par with directly connecting to motherboard
  • (MB991U3) Performance is excellent when coupled with SSD
  • IcyDock finally has a 2.5" external solution (their USB2.0 options were retired long ago)

  • MB991 could benefit from better dust-protection (anti-dust flap, etc.)
  • MB998 doesn’t have a switch for fans
  • MB998 drive caddies can be tough to line up, easy to bend or damage
  • ToughArmor is still a premium product line with a premium price compared to other vendor solutions.


Yes nice review, you got with it first because I was about to write one. Have 2 of those (MB998SP-B) and working like charm filled with SSDs. I would add however to list of Pros and Cons one detail.

Pro: removable fans, yes oh yes.


If you screw backplane with thumbscrews (M3) for easy access you need to use M3 washers. Thumbscrews without washers will obstruct mounting of 2 or 4 drives (depend on how many screws is used 4 horizontal, all 8, or 4 diagonally). Keep in mind this little detail.
@Ypsylon: Yes, IcyDock's instructions made a point about using their supplied screws for mounting the bay. If the screws are too long, they'll stop the sleds from sliding all the way back into the unit.

I wouldn't exactly say the fans are removable by design. Yes, they're screwed in and you can unscrew them, but I actually prefer the forethought IcyDock gave the MB994SP-4S with the toggle switch.

Overall, very solid product though.
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