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Nero DVD Speed, What does all that data mean?

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Nero DVD Speed, What does all that data mean?

Postby Malign on Thu May 29, 2003 5:17 am

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This is the result of the Samgung Combo drive. I tried DVD speed in Nero, and these are the results.. I used the DVD of Final Fantasy, disc one. Why does the drive not touch the maximum 16 speed? Also, why does it peak and fall in the centre, instead of just arcing up like Nero CD speed?
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Postby Malign on Thu May 29, 2003 5:19 am

Like a true newbie, i have posted in the wrong forum. Sorry bout that. If anyone could answer the topic, i would be blessed.
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Re: Nero DVD Speed, What does all that data mean?

Postby Inertia on Thu May 29, 2003 9:09 am

Malign wrote:
This is the result of the Samgung Combo drive. I tried DVD speed in Nero, and these are the results.. I used the DVD of Final Fantasy, disc one. Why does the drive not touch the maximum 16 speed? Also, why does it peak and fall in the centre, instead of just arcing up like Nero CD speed?


The DVD disc you are using for the test is a dual layer disc. These discs always transfer data as reflected by your graph. When the first layer is accessed the transfer rate gradually increases until the second layer is accessed. The transfer rate then begins a gradual decline. Because of this a dual layer disc has much slower transfer speeds than single layer discs. A single layer disc would produce the straight line type of graph you are looking for.

Because of the extra time provided by the format, most movies are dual layer discs.
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Postby Malign on Thu May 29, 2003 1:41 pm

Explained to perfection. Thanks for the post.
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Postby Malign on Thu May 29, 2003 1:46 pm

This CD writer + DVD combo says has 16x dvd speeds, how come its so slow? Is it because of the media I am using?
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Postby Inertia on Thu May 29, 2003 5:44 pm

I am not sure what your reference is to being "slow".

If you are referring to a 16X DVD speed as being slow compared to a 48/52X CD-R speed, consider this:

At 1x speed, a CD has a velocity of 1.2 meters/sec.
At 1X speed, a DVD has a velocity of 3.49 meters/sec.

As you can see, a DVD is spinning 2.9 times faster than a CD for the same reading speed.

A DVD speed of 16X is equivalent to a CD speed of 46.5X.

Not so slow, is it. :wink:
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Postby dhc014 on Thu May 29, 2003 5:55 pm

Malign wrote:This CD writer + DVD combo says has 16x dvd speeds, how come its so slow? Is it because of the media I am using?


Your drive should reach about 16x if you can find a large, single layer DVD to test on. 16x is the maximum speed and will only be reached at the end of a single layer disk.
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Postby cfitz on Thu May 29, 2003 6:52 pm

Inertia wrote:At 1x speed, a CD has a velocity of 1.2 meters/sec.
At 1X speed, a DVD has a velocity of 3.49 meters/sec.

As you can see, a DVD is spinning 2.9 times faster than a CD for the same reading speed.

A DVD speed of 16X is equivalent to a CD speed of 46.5X.

In terms of data transfer rates the difference is even more pronounced, because the lineal density of the DVD data is greater as well. Measured in bits/sec, 1x DVD = 9x CD, so that at 16x a DVD is transferring data at a 144x CD rate.

As both Inertia and dhc014 have said, in order to reach the full 16x rate you need a single-layer disc that is filled to capacity.

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