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Enermax EHD-251-U2 USB 2.0 2.5 Enclosure Review



Enermax EHD-251-U2 USB 2.0 2.5 Enclosure


I bought this enclosure because Enermax has a decent brand reputation. Also, the price was slightly higher than the other enclosures in, so I thought it would be better quality. As soon as I took it out of the packaging, I knew this was a poor quality enclosure. Now I will go on to explain why.

I immediately noticed two problems with this enclosure. First, this enclosure is much larger than the other two I have reviewed (Nexstar and PCAlly). It is wider and taller because of the 1/4" thick plastic spacers on the ends. It is thicker because it has a "screwless" design where the drive sits on a tray that slides into the enclosure. The other two enclosure have little to no extra space around the sides of the drives. The second problem is that the plastic ends feel really cheap, brittle, and flimsy, like the plastic used for CD jewel cases. For a product vouching to be portable, this is outrageous, since knocks and bumps are to be expected in these circumstances.

The installation procedure is as follows. On the end cap, there is a springed latch that must be pressed down. This releases the tray inside the enclosure, which is pulled out by grasping the other end cap. Thus, the enclosure claims to be "screwless", because you can open and close it without screws. But when I pulled out the tray, much to my surprise, I found a package of four screws! These are intended to attach the drive to the tray. I can't understand why one would want to remove the tray, but not the drive attached to the tray. Luckily, I was able to do testing without screwing the drive onto the tray. You be the judge of whether or not this drive is truly screwless.

True to my first impressions, the drive did not even work properly. I first tried the USB cable alone, but unlike the other two enclosure, the drive did not spin up and it was not recognized by Windows XP (SP2). Only after plugging in the PS2 power cable did the drive spin up and become recognized in XP. Plugging in the PS2 power cable was a pain. I have both a PS2 mouse and PS2 keyboard, so I had to unplug the mouse to make room. Luckily, the PS2 connector has a passthrough, so I could plug the mouse back in. Just imagine doing this routine at every computer to which you brought the drive. Worse, most computers don't have PS2 ports on the front of the case, and PS2 'hubs' do not exist, so you always have to go into the back of the case. The USB plug that goes into the enclosure is the smallest Mini-'B' style plug, which I found harder to use than the more popular and larger 6mm size Mini-'B' plugs.

Once powered on, the whole, clear, plastic side of the enclosure lights up with an obnoxiously bright blue LED. The other side lights up bright red by another LED during activity. The lights are so bright, you would think it was Divali, the Indian festival of lights. Unless you are a five year old, I suspect you won't be impressed by this lighting style.


Even fully plugged into the one year old Asus A7N8X Deluxe motherboard that has minimal load on the ports, the drive was unreliable. It failed several times with errors like following:

"Windows - Delayed Write Failed
Windows was unable to save all the data for the file F:\Test\LargeRandomFile2.txt. The data has been lost. This error may be caused by a failure of your computer hardware or network connection. Please try to save this file elsewhere."

Ouch! I had to unplug the mouse in order to get the drive stable enough to copy the test file from it! The copy succeeded, but the read speed was a pathetic 13.1 MB/second. By comparison, the PCAlly was 13.6 MB/second and the Nexstar was over 26 MB/second. These tests used the same configuration and drive (Samsung MP0402H 40GB 2.5" 5400rpm notebook hard drive).

Copy 1GB test file between external enclosure and local hard disk.
Read speed 13.1 MB/second
Write speed 13.1 MB/second (test failed midway)

I was unable to copy the entire 1GB file to the drive, because of its failures. For the brief moment it worked, it went about 13 MB/second (as viewed in performance monitor). At that point, I gave up with it and repacked it for RMA. This is why there is no Sisoft benchmark for this enclosure.


Avoid this enclosure like the plague. Do not be fooled by its Enermax brand name and high price. It is too big, too cumbersome to plug in, too flimsy, too bright, too slow, and to top it off, it barely works. If there were a worst product of the year award, the Enermax EHD-251-U2 would win it hands down.

Not all USB 2.0 enclosures are the same. So far, of the three 2.5" enclosures I have reviewed, the NexStar, despite its minor problems, is the best due to its ability to operate on a single USB port and its incredible speed.


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Created 2004-09-15, Last Modified 2011-07-24, © Shailesh N. Humbad
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