More Bandwidth with USB 3.0

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Casper42

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Why is it that articles like this continue to perpetuate the rumor that USB 2.0 does 480Mbps. Connect an external HDD and try copying a large file over to it. You wont see more than 35MB/s and in most cases its right around 30MB/s.

This is because the 480Mbps (60MB/s) is for both directions AT THE SAME TIME.
If your copying data from 1 USB device to another, this is helpful, but the fact still remains the transfer rate between the PC and either of the drives is still going to be limited to 30MB/s

I would venture to guess that the 4.8Gbps transfer rate in USB 3.0 will be the same and therefore a file copy to/from a USB3 HDD will be limited to around 300MB/s. While this sounds great, and will likely satiate the needs of the traditional HDD market, this is basically the same speed as SATA 3Gbps that has been on the market for a few years now and will soon be replaced by SATA 6 Gbps in the next 12 months.
 

thartist

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has anyone here ever had a 4mb song transfer in 0,1 secs to a pendrive?? or a 40mb album in 1 or 2 seconds?? ...i guess the chart is about theoretical limits.
 

archange

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According to my book, speed is NEVER enough... So, "Is 5 Gbit/s Too Much?" - definitely not, not with the current progress rate of flash drives. Casper42 has a good point.
 

apmyhr

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I hope most external hard drives will be able to operate without AC power now. Hopefully, even the big ones. Although the increase in power sounds kind of moderate, so I wont get my hopes up.
 

belardo

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The power issue with 2.5" external HDs is not so much the USB spec itself, but the chipset. Intel made the original USB, Apple made it marketable by having it on all their computers and then AMD makes it work better on their motherboards.

I have both intel and AMD CPU/Chipsets. And noticed this at some of my clients offices as well.
- ALL the intel systems required two USB connectors to power a 2.5" HD.
- The AMD systems (32bit, 64bit single / dual cores) did not. A single cable works fine.

The other issue... performance.
When backing up Gigabytes of info... backing up about 170GB of data with an AMD64 system takes about 2hrs. With an intel Q6600/P35 (and the other Core2 systems)it takes about 5 hours! Same Ext. USB drive. It sucks... nobody has explained why this happens.
 

belardo

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Ah, read more article.

1) SuperSpeed? Just stick to the version numbers. Its easier to remember than HighSpeed and SuperSpeed... what was USB 1.1 called? Whats next, SuperDuperSpeed? Then after than, Ludicrous Speed?

I've yet to every meet any human who called USB 2.0 as "Hi-speed".

2) USB 1.1 was a godsend for what it did back then. Flash keys were in the mb... not GB. so it wasn't so bad. I used Firewire to xfer video to the PC. Even today, USB 2.0 is respectable even with todays HDD-Camcorders.

It takes a few minutes to DL a 30~40mins of video recording. That is NOTHING compared to working with tape connected to an analog A/V card... even firewire from a Sony camera takes a long time (but with firewire, its perfect). 30mins of video = 30mins to convert/transfer. Having it take seconds is quite cool... in the future.

My next PC ugprade must have (hopefully): DX-11 Video card (ATI 5850), USB 3.0, PCIe 3.0.
 

sublifer

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[citation][nom]Casper42[/nom]WI would venture to guess that the 4.8Gbps transfer rate in USB 3.0 will be the same and therefore a file copy to/from a USB3 HDD will be limited to around 300MB/s.[/citation]
Read or check the spec's on USB3 before you start criticizing... they stated in the article that it supports full speed both sending and receiving. Also, USB is not limited to 30MBps in either direction, it is limited to ~60MBps combined... but is most often limited by the USB controller to sata(or IDE) interface and translation.

I do agree that it will be too little, too late but it sounds great for now with the exception of the 3m cable limit. They really need to work on their transmission distance.
 

avatar_raq

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I agree with Casper42, real life transfer rates never got near the advertized rates, whatever the reason is, whether it's false specification or a bottleneck with the southbridge, I don't expect USB 3.0 to be any different in that regard. In fact if the problem is a southbridge bottleneck then expect a big disappointment in motherboards supporting USB 3.0 especially the early generations.
 

bourgeoisdude

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[citation][nom]Belardo[/nom]1) SuperSpeed? Just stick to the version numbers. Its easier to remember than HighSpeed and SuperSpeed... what was USB 1.1 called? Whats next, SuperDuperSpeed? Then after than, Ludicrous Speed? I've yet to every meet any human who called USB 2.0 as "Hi-speed".[/citation]

I know you haven't met me before, but for the record, I call it that.
 

hellwig

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USB 3.0 utilizes an 8b/10b encoding, which is also being used by Serial ATA. 10-bit words are represented in a 10-bit encoding
Actually 8-bit words are represented in a 10-bit encoding. I want real-world specs. How close to 500MB/s can it really get? Also, no USB1.1 support? So I can't plug my keyboard or mouse into a 3.0 hub? I'm pretty sure my keyboard and mouse don't use the 2.0 protocol.
 

aspireonelover

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Both my keyboard and mouse use the usb 2.0 interface, so I'm on the lucky side.
But is USB 3.0 really that necessary? IMHO, no. USB 2.0 is good enough for everything, and it even exceeds the current rate of the fastest flash drives on the market.
It will become useful one day though, we just don't know when... 2010? 2011?
 

jrst

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[citation][nom]Casper42[/nom]This is because the 480Mbps (60MB/s) is for both directions AT THE SAME TIME.[/citation]

No; USB is half-duplex. Information only goes in one direction (in or out) at any given time on any given USB bus, but does so at 480Mbps (for high speed). The reason you don't see faster xfer rates is due to protocol overhead and sucky implementations.
 

matt87_50

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if there isn't enough power supplied to power a 3.5" drive, they have completely missed the point! i would rather a port that lets me plug in a 3.5" drive with no power cord requirement than one that can transfer at a gazilion bytes a second but still requires a bulky brick power supply and free power socket.
 

kato128

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[citation][nom]aspireonelover[/nom]Both my keyboard and mouse use the usb 2.0 interface, so I'm on the lucky side.But is USB 3.0 really that necessary? IMHO, no. USB 2.0 is good enough for everything, and it even exceeds the current rate of the fastest flash drives on the market.It will become useful one day though, we just don't know when... 2010? 2011?[/citation]

I am regularly bottlenecked by the slow speed of USB 2.0 devices and currently pick eSATA over it every time. Try transferring 70GB of data over USB 2.0 and then tell me we don't need USB 3.0.
 
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