Why is USB3.0 so slow?

Toggle sidebar Toggle sidebar
Status
Not open for further replies.
V

vivski

Distinguished
Oct 21, 2010
36
0
18,530
I am using Win7 64bit Pro on my Asus Rampage Extreme board and have installed a Scan HPU-300NC USB3.0 Super-speed PCI Express Adapter and connected it to a Verbatim USB 3.0 Desktop Hard Drive.

As USB3 runs at, (theoretically), 10 times the speed of USB2, (although a six times speed increase is quoted as more likely to be achieved), I had expected a considerable improvement over the speed I currently achieve with my Buffalo USB 2 hard drive.

In fact, when transferring a large number of small files I only see an increase of about 50% and transferring a 49Gb file the speed is only about twice as fast, both according to the transfer rate shown in the pop-up window and by my own timing.

Can anyone explain why the difference is so small?

Viv
 
If you take your mechanically limited to 120MPH car and drive on the autobahn, will you go faster? Why should your drive transfer faster just because the interface is faster? That would only happen if the interface is the bottleneck.
 
Sorry, I do not understand the point you are making.

Are you saying that it is impossible to get USB3.0 to work with the motherboard or OS that I am using?

Both the interface card and the disk drive are USB3.0 so I think that I should be able to achieve much higher speeds than I am currently seeing.

Viv
 
4745454b is saying that the harddrive itself is the limiting factor, not the interface. The drive may have a faster interface than your Buffalo USB 2, but the internal hard drive of Verbatim can on write the data so fast. The analogy is the hose connection is ten times bigger, but the drive your transferring from/to are now the bottlenecks.
 
It's more simply put this way. Just because you get an HDTV, doesn't mean you get an HDTV picture. You need something that is providing the HDTV signal to get the pretty picture. TV + DirecTV/Dish/Digital Cable = Pretty Picture.

Same goes for USB 3.0 or any new computer technology.

USB 3.0 Interface + USB 3.0 HDD = 6-10x speed increase
USB 3.0 Interface + USB 2.0 HDD = USB 2.0 Speed
 
Interesting, but as Verbatim advertise this drive as USB3.0, and this is the only connection to the hard drive then I am puzzled.

The blurb on the box says "Verbatim's super speed USB 3.0 Desktop Hard Drive provides high speed capacity storage back up, giving a fast and safe solution t back up files from your PC or laptop. USB 3.0 is up to 10 times, (based on theoretical bus speed of 4.8Gbits/second for USB3.0), faster than USB 2.0 and is backwards compatible with USB 2.0 devices."

As both the interface card and the drive are claimed to work using USB 3.0 then I cannot see that either of them are causing the problem. And I am using the cable supplied with the drive, which I assume is a USB3 cable.

Viv
 
So your peddling your bike at 25MPH on a street with a 25MPH speed limit. (or interface.) You then go on the freeway with a 55MPH speed limit. (interface) Can you peddle 55MPH? If you put a drive on a USB 3.0 interface can it actually transfer data that fast? You haven't listed your transfer speeds so I have no idea if this is the case, but I'm pretty sure you are simply expecting speed that isn't there.
 


Hi, let me make this a bit clearer to you.

HDD mechanical speed limit 100MBytes/s

On usb 2.0 HDD tryes to shuv 100MBytes/s practical (800Mbps transformed into theoretical) trough a 60Mbytes/s practical (480Mbps theoretical ) pipe this means it wont go faster then 60Mbytes/s. (USB is limiting factor in this case)

On usb 3.0 HDD tryes to shuv 100Mbytes/s practical trough 600Mbytes/s practical (4.8Gbps theoretical) pipe this means it wont go faster then 100Mbytes/s. (HDD is the limiting factor).


What they want to tell you is that you USB 3.0 does allow for insane speed but the actual HDD in the enclosure is unable to deliver.

And then theres the thing with a lot fo small files that was allways degrading performance compared to big files as the HDD also has to write FAT entries that are situated at the start of the Drive many times moving the Head back and forward instead of continuously writing data. unless you use a SSD you will allways have problems with small files due to seek/latency.

I hope this is clear enough i tryed my best to be as descriptive as possible.

USB 3.0 is not at fault here you mobo is ok the hard drive inside the enclosure is too weak. Besides if you want insane speed try a SSD in one of those USB 3.0 enclosure, if you can afford it.
 


Thank you, as you will see in my original post I am using a USB3.0 interface and USB3.0 HDD, but only achieving a speed increase of about two.

Viv
 


Thanks, I have emailed Verbatim to see if they agree that it is the hard drive which is causing the problem. If so then they are breaking the Trade Descriptions Act 1968, which seems unlikely to me.

Viv
 


Transfer speed using USB2.0 to my Buffalo drive for a 50Gb file is about 32Mb/second, taking 52 minutes, but via my USB3.0 interface card to my USB3.0 Verbatim drive the same file is transferred at about 45 MB/sec in 29 minutes. As the speed varies over time I have quoted how long it takes to give a better indication of the speed difference.

Viv
 
Its not untypical for a company to missadvertise they're products using the peoples missing knowledge to they're advantage.

The advertisment is not untrue USB3.0 offers 10 Times the speed bandwidth, while omitting the fact that the actualy real transfer rates achieved are way smaller.

To place this in perspective you would need at least 3 OCZ VERTEX 2E 120GB set in RAID 0 to be able to saturate a 600MBytes/s bandwidth.

The fastest non SSD drive i've tested so far is the Samsung Spinpoint F4 2TB Eco Green that has at its best a troughput of 137 Mbytes/s at its best.

Just like ISP advertise a 20Mbit connections when in fact your transfer rates is 20/8=2.5Mbytes/s but its even less as for them 1MB=1000KB when in fact computer storage 1MB=1024KB this leads to further loss.

Ground line is 1Byte=8Bits.

Don't ever belive what people advertise, they find any loophole available to tell you stuff you don't understand just to impress you. Its why we have Tom's Hardware so they can tell us the real deal and not just sweet honey stories.
 


Sounds like the typical perfomance of a mediocre 2.5" Laptop HDD running at 5400RPM.
 


They are not false advertising. There is no such thing as a USB3.0 hard drive. The USB3.0 only describes the hard drives interface, that is it's connection to the motherboard. If the hard drive is a 7200RPM hard drive then the drive will always spin at that speed no matter what the interface is. So, the hard drive will always pump the same amount of data across the interface, unless the interface itself is rated slower than the hard drive at which point the interface becomes the bottleneck.

Think of it as an assembly line. The person is the hard drive and the conveyor belt is the interface (USB). You can keep increasing the speed of the conveyor belt (up to USB3 speeds), but at some point the person won't be able to work fast enough to keep up with the belt.

Ok, anyone else want to try to explain this? 😉
 
Your keyboard and mouse connect to the computer use USB 2.0, which is capable of transferring (in theory) up to 60 MBytes/sec. Can you type 60 million keystrokes per second? No. Does that mean that the manufacturer of your keyboard is lying when they claim it connects via USB 2.0? No.

It's perfectly valid for the manufacturer to label a hard drive as "USB 3.0" and it actually does mean something important - it means the drive will NOT be limited to the ~35MByte/sec throughput that USB 2.0 can manage with hard drives. USB 2.0 is a bottleneck for hard drives, and so USB 3.0 drives are a big improvement over USB 2.0.

USB 3.0 is a standard connector and protocol that allows transfer rates up to 400MBytes/sec. But no current hard drive can actually transfer data that fast - so the hard drive itself is a limiting factor. But the new standard is designed for the future and it will still be useful several years from now when hard drive transfer rates are even faster.
 


Correct, it is faster, but it is not as fast as reviews I have seen, (http://www.engadget.com/2010/01/09/usb-3-0-superspeed-gone-wild-at-ces-2010-trumps-even-your-new-s/), which suggest that six times is achievable using a HDD. Verbatim's website says the drive's spec is :-

Cache: 8MB or higher
Drive: SATA - Hi-speed
External power: +12VDC Input
Interface: 1 x USB 3.0
Drive dimensions: 202 x 114 x 40mm (L x W x H)
Product weight: 1KG approx.

I believe that SATA Hi-speed means that the internal transfer rate to disc is 3Gb/sec, roughly 60% of the transfer rate achievable via USB3.0, but still six times the USB2.0 transfer rate.

Therefore I do not believe that the disc drive is the largest limiting factor, especially as the website I quoted above has achieved a transfer rate of 135Mb/sec to a Buffalo external enclosure using platters.

Viv
 
Hard drives transfer data a lot more slowly to the end of the disk (innermost cylinders) than the beginning (outermost cylinders). A drive with a peak transfer rate of 135MByte/sec will probably only transfer somewhere around 60-70MByte/sec in the region of it's last logical blocks.
 

Instead of USB-3, Intel should have promoted Fire wire as the better alternative. The better alternative was Apple's ADB bus. It was designed for the small number of input devices (keyboards and mice) that were in use. USB is just another mish-mash that started out reasonable, but got more and more involved.
 
This will most likely be my last post on this subject, I simply can't think of any other way to explain this and the OP obviously doesn't understand.

On the other end of this one was a Buffalo external enclosure stuffed with an old-fashioned, platter-based hard disk, which still delivered perfectly absurd transfer rates of about 135MB/sec.
Click to expand...

First, we have no idea if this is max or average. Second, we have no idea if the harddrive in your external unit can hit 135MBps. The only spec that gives us a clue about its speed is that it has 8MBs of cache (or more), which was common years ago. I think my Seagate 7200.10 drives that were new back in 2003 or 2004 have 8MBs of cache. 32MB is common on the modern drives, with 64MB soon to be standard. My 7200.10 drives can do around 60MBps average if I remember correctly, so if you have a similar drive inside yours then 45MB isn't that much slower. You can't compare yours to that article because we completely lack info on both drives in question.

So why did the mechanical drive score only 135MBps when the SSD did 200? Doesn't USB 3.0 allow for ~600MBps? Why are both drives going so slow? Using your logic both of those drives should be transferring much faster. Until you can figure out what drive you have inside your unit, you won't know how fast it should be. I still get the feeling its fine, and that 45MB avg is simply normal for your drive. You can't peddle 55MPH, and your drive can't do 135MBps.
 
I have pedaled 55 mph downhill
Basically, your hard drive is faster than the limitation of USB2.0 and with USB3.0, the bottleneck returns to the hard drive, which is capable of 45mb/s regardless of how fast the connection is.
 
USB 2.0 and 3.0 are just interfaces. They do not dictate how fast a HDD truly is. Say a HDD has a max transfer of 45mb/s using usb 2.0. Take that same HDD and use USB 3.0 with it the max transfer will still be 45mb/s. As others have said it is simply that the HDD that Verbatim used is not capable of faster speeds. USB 3.0 has already alleviated the interface bottleneck and whatever speed you're getting is what it is capable of.They haven't lied to you in any way as they were not talking about the speed of their drive, but rather the theoretical speed of the interface. Companies love to do that as it is perfectly legal, but is very misleading and easily tricks uninformed consumers.
 
to the OP, do you realize you are also limited by:
1. What your PC is currently doing? USB has CRAZY overhead.
2. Did you ever change the power/performance PROFILE? If your Power settings are default, and not PERFORMANCE, usb can lose a TON of speed. The reason USB is cheap, and widely used is that it is CHEAP. It uses your system resources to do it's job. It has no dedicated controller (like firewire has) and therefore the rest of the system needs to act like the "traffic cop".

And then you try and use your system for other things, and everything starts slowing down as windows tries to even out priorities.
FIREWIRE will always be superior to usb. It doesn't take much overhead at all. Maybe for the driver but that is about it.

So disable everything in your pc in Windows aside from what windows uses, and you may get more speed but no matter what you will NEVER hit the USB 3.0 spec

Basically in a nutshell, you cannot complain about an interface/technology when you are getting a faster rate (in this case usb2 to usb3). There are WAY too many variables with USB
 


Wow, I've never seen so many people posting unclear analogies to a person who doesn't understand technology in my life. It's like a kangaroo giving birth to a baby tigress, the tigress has a difficult time coming out but it's much more powerful than a flyer. Or, it's like an UFO caught on film and played on CNN, the UFO has much better tech than the CNN satellites broadcasting the video. And I've also never seen so many people get upset when the OP doesn't understand you're unclear explanations.
 
Status
Not open for further replies.

TRENDING THREADS

Latest posts

Moderators online

Share this page

COMPANY
RESOURCES
FOLLOW
Top Bottom