USB2 Transfer Rates

[Cattywampus_]

Hi,

I need some information regarding USB2 Transfer rates.

I have a Macbook Pro, 3 External Hard drives (all USB2) and an LG Ext. DVD Burner (USB2). They all plug into a D-Link USB Hub, that then plugs into one of the 2 USB ports on my MBP. The other USB port on the MBP is taken up by a keyboard (I run the computer lid-closed + ext monitor).

Now, the reason I bought the External DVD Writer is because the Superdrive in the MBP is only a 4x, which is simply not good enough. So the 16x External drive is so I can burn a full 4.7GB DVD in around 5 minutes yeah?

I ordered some Datawrite Titanium 16x DVD-R discs with the drive as well. I have only burnt one thing so far and i wasn't impressed.

Majority of the DVD burning i will be doing will be from any of the external hard drives. The first burn I did with the new drive+disks took around 10minutes (burning a DVD Video TS folder in Toast). I was quite disapointed as i thought it would fly. I am hoping that it is not because the HDD's and the DVD Writer are both on USB2?

Is it possible that i am saturating the bandwidth by reading from the USB HDD and writing that info to the USB2 DVDRW?

When i was burning I had nothing else running that could tax the system?

Ideas? (unfortunately I cannot tell in Toast what speed and how much data is actually flowing through at the time of writing - am looking for a burning app for MacOSX that shows me that).

 

[live4ever]

Plug the burner into one USB port and the HDD into another see if this improves speed.

Are you burning at 16x in Toast or at the best speed? 10 minutes is not bad to burn and verify the disc.

 

[PlaceofDis]

the problem with USB 2.0 is that it works in a burst transmission so there is never a steady rate of data transfer. a FW 400 DVD burner would be much better since FW works at a steady transfer speed, same with the hard drives really to be honest, and they could be daisy-chained too.

the bottle neck is that USB 2.0 since it doesn't have its own chip and its transmission method.

 

[Cattywampus_]

Plug the burner into one USB port and the HDD into another see if this improves speed.

Are you burning at 16x in Toast or at the best speed? 10 minutes is not bad to burn and verify the disc.

Burnt at best speed as far as I can remember - and i didnt verify it. 10minutes is from when I click record to when it spits the disc out once its burnt.

 

[ericssonboi]

the problem with USB 2.0 is that it works in a burst transmission so there is never a steady rate of data transfer. a FW 400 DVD burner would be much better since FW works at a steady transfer speed, same with the hard drives really to be honest, and they could be daisy-chained too.

the bottle neck is that USB 2.0 since it doesn't have its own chip and its transmission method.

* 2

Try changing the enclosure to Firewire..
Burst speed sucks!!!

 

[Cattywampus_]

Well I cannot change it to Firewire as its a USB2 drive.

I could move the hard drives over to FW400 and daisychain them all - but the DVD RW would have to remain on USB2. Will have a play with it 2nite.

 

[garethlewis2]

Maximum sustained transfer speed of USB2 is 4 megabytes a second. They may improve it in future.

 

[Cattywampus_]

Great. Absolutely marvelous.

I moved the external hard drives over to FW. With just the DVDRW on USB2. Still is going dog ass slow. After poking around the internet it does infact seem that Apples implementation of USB2 is ****e.

So now I am stuck with a USB2 DVDRW that I can't even write at full speed with. Seriously pissed off.

Is there no converters I can get to convert the USB plug to a Firewire plug so that it goes via the firewire chipset or is that just not possible?

 

[deadpixels]

maybe this could help

seen here
a bit expensive though, maybe its cheper to get a new burner

 

[PlaceofDis]

Maximum sustained transfer speed of USB2 is 4 megabytes a second. They may improve it in future.

no this is flat out incorrect. USB 2.0 has a theoretical maximum of 480mbps it is not a sustained transfer protocal, but instead works in burst transfers. it can, in theory, reach up to 480mbps, but rarely does.

FW400 is a sustained transfer protocal, due largely to the fact that it has its own processor of sorts, one on the device and one on the machine, whereas USB relies on the regular processor of the host machine.

Great. Absolutely marvelous.

I moved the external hard drives over to FW. With just the DVDRW on USB2. Still is going dog ass slow. After poking around the internet it does infact seem that Apples implementation of USB2 is ****e.

So now I am stuck with a USB2 DVDRW that I can't even write at full speed with. Seriously pissed off.

Is there no converters I can get to convert the USB plug to a Firewire plug so that it goes via the firewire chipset or is that just not possible?

Apple doesn't implement USB 2.0 any different than other vendors. its a limited transfer medium, in my opinion. its a standard protocal, and trust me, Apple doesn't do anything different to make it any different than other vendors. and no there is no converter. different chipsets and protocals can't interact. could possibly by an enclosure and switch the drive from your current enclosure to a new one, but who knows if thats possible...

 

[bousozoku]

the problem with USB 2.0 is that it works in a burst transmission so there is never a steady rate of data transfer. a FW 400 DVD burner would be much better since FW works at a steady transfer speed, same with the hard drives really to be honest, and they could be daisy-chained too.

the bottle neck is that USB 2.0 since it doesn't have its own chip and its transmission method.

It could be more reliable to provide a consistent speed if other applications are minimised, since the CPU has to control the process.

 

[Cattywampus_]

Right well

When I was burning a DVD at what is supposedly 16x - on 16x media, it would spin high, then after burning 30seconds (not the Write In, once its started burning the actual data) it seems to spin down.

Watching "Disk Activity" in Activity Monitor it says there is around 10-12mb/sec going through. So that is no where near the 21mb/sec needed for 16x DVD burning

So if USB2 implementation is exactly the same as any other Win computer, why can I not burn at the 16x I am supposed to be able to.

 

[theBB]

Not every USB2 device is the same quality. Can you try another, maybe more pricey, DVD writer?

 

[Elisha]

maybe the drive is not caching properly.....try another drive would be my suggestion as well. but a FW drive would be alot better.

 

[Cattywampus_]

Right

I think I have found the problem.

I updated the firmware on the drive (its an LG GSA-E10L). I connected it to my Dell laptop and burnt DVD at 16x using Nero in about 5minutes. So its not the burner that is the problem.

So I connected it back to my Mac hoping the firmware had solved it. First of all I burnt a load of files filing a disc through finder. It burnt that in around 5minutes. Great I thought.

I popped another disc in, loaded up Toast. It started off as normal - the drive revved up to full speed - and then after a minute it drops out and starts writing at about 8x. Just like before. I then decided to get hold of a copy of that Disco beta. I just burnt the same image I tried in toast in five minutes, compared to the 8minutes it takes in Toast.

So it appears that Toast has trouble writing at full speed. Which completely sucks ass as its a kick-ass program.

 

[hayduke]

So it appears that Toast has trouble writing at full speed. Which completely sucks ass as its a kick-ass program.

It is?

I think a kick-ass program will perform as you need it to. I think Toast is turdly. It's not even shareware. Meh.

 

[Cattywampus_]

Well it has a lot of features - its a nice all in one package that can do pretty much anything with regard CD/DVD burning - i am just curious to know why it cannot handle burning at 16x for me. :/

 

[Mobility151990]

have you got buffer underrun prevention turned on? I find toast spins down if i start to move the laptop or have other programs, try keeping the laptop perfectly still with no other programs running other than toast.

 

[Cattywampus_]

Buffer Under Run is turned on.

The computer is always still - and I shouldn't really have to have nothing but Toast running to burn a DVD at full pace.