WHY USB 3.0 HDD enclosure behave as...

Hi all guys, please forgive me always to find out solutions or suggestions in different forums by the way of post-reply. I thought it tends to be more reliable and prompt. Recently I bought a new Macbook. I use it with this enclosure frequently in my job. Inateck 2.5 Inch USB 3.0 Hard Drive Disk HDD External Enclosure Case with usb 3.0 Cable for 9.5mm 7mm 2.5" SATA HDD and SSD, Tool-free HDD Installation, Compatible With Windows 2000/ XP /Vista/ 7/ 8, Mac OS 9.1/10.8.4: Amazon.co.uk: Computers & Acces

I have to say it is of good quality. portable and easy to operation . But I just encountered a problem that it doesn't behave at a stable transfer rate as the list describe sometimes . This is the first time I use this kind of products. Some people say it is normal because the speed must be influenced by other processes.Some people says it is the reason of my HDD. Even some says the problem comes from my Mac.
I really wondered whether I have bought the wrong item although I like it very much.VERY complicated experience.Do you have any advice?

 

Larger, less numerous files will transfer faster than smaller, more numerous files as the drive heads have to find where each of the smaller files may be, whereas larger files are find once-read for a few seconds then move on to the next. It takes more time to find the files than it does to transfer them unless the file is larger than a certain size.

Exactly what are you trying to shuffle around?

 

Wow, been a long time since posts from a new non spammer member got flagged as spam, sorry for that.

On to the topic:
The transfer speed will vary depending on what drive is in the enclosure and what kind of file you are transferring. USB3.0 is rated at 5 Gbps theoretical max transfer rate or 650 MB"s if you prefer, but you're never going to get that although it is usually what is advertised by the manufacturers. There are basically four things that won't allow you to get those transfer speeds:

• Overhead: information that has to be transferred along with your data and that is needed for the USB communication protocol, etc. That will already remove a good chunk of that 5 Gbps.
• How good the USB controllers both in the enclosure and in your computer are: It can make a pretty impressive difference, especially if you have a not so good controller in the enclosure and there's no way to tell unless you open it up and check what brand and model the controller is and then try to find data on how good it is.
• The drive in the enclosure: A HDD, a good 7200 RPM one will top at around 100 MB/s sequential transfer rate, if you want to go over that, you'll need to use a SSD in the enclosure.
• The type of data you're transferring: Sequential (the larger the file the better up to a certain point) will give you the best results in terms of transfer speed. A lot of small files which amount more to random data transfers will go much slower depending on the size of the files. You usually end up with an in between scenario. If you're transferring videos that are hundred of MBs or a few GB in size, then you'll pretty much hit close to the max you can achieve, if you're transferring music files of a few MB in size, it will be faster than pure random data, but not as fast larger files and if you're transferring lots of files that are a few KB in size, it'll be even more slower.

You could also say that the USB3.0 drivers also have an impact, but drives can only do so much if the hardware isn't there. It's possible that you have a faulty enclosure too or just a bad one, but the best way to tell would be to either tell us what kind of files and the transfer rates you're getting or to benchmark it and post the results here.

 

thank you Kuu. What i am trying to shuffle around is simply some necessary drivers and important files stored in my old laptop originally.

Thank you for your detailed clear explanation. I thought I might eliminate the factors one by one as well. I will firstly use a SSD instead to see if it would behave better.As the transfer rates you mentioned , I am quite surprised at what you listed because the speed I test out is 40 mb / s write and 50 mb / s reading. Is it possible that I got the wrong data inaccurately?

 

Find a file that is a couple of GB in size and try transferring that, you'll know right away whether your enclosure is performing in the USB3.0 ballpark. The following images from left to right are me transferring a 19 GB .dat archive to a SSD on USB 3.0 and the other two are the same SSD in two different USB3.0 enclosures, one with an ASMedia controller and another with a JMicron controller. Both are giving good transfer speeds, but you can see there's a difference between the two.


With a mix of smaller and large files (a couple of drivers for my laptop), I got transfers fluctuating between 30 MB/s and 120 MB/s.

 

ok ,then from your answer, my enclosure may also have not any problem. I I am considering to ask my friend experienced than me for help to test my sample again when he is free. Thanks a lot!

 

You can also try a RAID HDD (in RAID 0) which should give you significantly faster speeds than a single drive alone.

It's also much, much more economical (under $300 for both 1 TB drives and enclosure) than a comparable sized SSD. Though not nearly as fast,.

 

Nice sequentials, small randoms are still at HDD levels, better than a single HDD and definitely cheaper than a SSD of the same capacity.

 

Thank you I clearly got you guys' point. The discussion between us is all focused on my HDD or SSD. So there is no business with my enclosure ,right? What l I have to consider is the change to what kind of hard drives.

 

I don't think you have to change anything, a SSD will definitely give you faster transfer speeds, but at what cost? For most of your uses, a HDD will do just fine.

I got a 128 GB and a 64 GB SSD in enclosures, but they are recycled drives. I changed those for larger capacity drives for the computers in which I was using them, so I thought, I might as well make use of them. Well, that and I did kill a flash drive from over use, so lesson learned (don't use it to shuffle around tons of data frequently).

I pull out the external SSDs when I know I might have to move with the data transfer still ongoing, no risk of damaging a SSD vs a HDD if you move it/drop it.

 

I generally think that SSD will indeed create the different performance compared with the HDD. But as you say, it seems that there is no need to worry about this problem. Thank you for sharing your experience and lesson with me. But I really did not figure out this sentence “I got a 128 GB and a 64 GB SSD in enclosures, but they are recycled drives. I changed those for larger capacity drives for the computers in which I was using them...”

 

In other words: I have two external SSDs of low capacity, but I didn't buy the SSDs for that purpose, I just reused parts I already had. Those SSDs were originally in my computers, but I replaced them with larger capacity SSDs and since I didn't really have a use for the 64 GB and 128 GB drives, I put them in enclosures. I didn't buy them for the purpose of making an external SSD.

 

Yeah, what you say sounds reasonable!!Maybe I have bought the exquisite one.Maybe I should not require too much because the performance is good enough to perfectly work all the time. It is the time to finalize the issue.Thanks.