If you get same version for instance 2008-1 it is the same.
The CD contains all the Scandinavian Countries + major roads of europe
So no street level navigation in Germany for instance
DVD has all the Euro Countries on Street level

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X5 4,4i-06 Current
330Ci Cab-03 2007-2008
MB E55 AMG-03 2006-2007
Z3 2,8 Roadster-98 2006-2007
X3 2,0d-05 2005-2006
320d-99 1999-2005

There are 3 x points here:

1. Difference in CD vs DVD media
2. Difference in reading speed between CD and DVD
3, Difference in map detail between CD and DVD

Point 1:
Whether it is a CD, SL-DVD or DL-DVD just impacts the amount of storage space required by the map.

Maybe the Scandinavian maps are smaller than 700MB so they will fit a DVD.

All of Europe requires a DVD due to the map size, and in fact, from 2008-2 it is now a dual-layer DVD (DL-DVD)

In my home country, the most modern map is only 80MB, so there is no need or reason to store it on a DVD.

Point 2:
Reading speed of a CD is the data transfer rate, and depends on the hardware spec of the CD reader. It varies from 1x (150kBps) to 52x (7.8MBps). I don't know the data transfer rate of the nav drive, I believe it is low as the data is cached in memory.

Reading speed of a DVD ranges from 1.35 MBps (1x) to 168.75 MBps (16x)

To determine if it makes a difference, take a CD map and copy it onto DVD:
then make a sequence of tests to see if the DVD works quicker...

Point 3:
What the map maker makes varies from region to region.
If for example you have a 2008-2 issue of the Scandinavia CD and the same issue date of the DVD, the data may be exactly the same, or maybe the map maker reduced the data set for the CD to save space.
You won't know until you compare them side by side, looking at a familiar area.
Note that what takes up a lot of map disc space is the POI data, and the various language versions. So you need to see if the amount of POI data is the same, and the quantity of supported languages is the same. This is because the POI info (hotel descriptions etc) is replicated in each supported language.
The Europe DVD normally supports at a minimum the 7 x standard languages of the BMW (GB, US, DE, FR, IT, ES, NL)

One of the first things you should check on your car is whether the Mk4 nav unit has the current release of operating software. Look in the top right of the settings screen. Current release, from March 2008, is versions 4-1/100 (which displays as 4-1/00). If you have older, eg: 4-1/80, 4-1/50, etc, then you should upgrade the nav software. This is a simple process and is described on this board in detail.

Thanks, both of you.

Jochen,

With the aid of this marvelous forum, I did infact upgrade my software just recently, without any problems. I went from V.23 to V.28.

I guess you have a point by saying the map data may be the same on the Scandinavian CD compared to the Euro DVD, so I think I will go for a DVD-upgrade instead of a CD-upgrade. Then I won't have to worry about reading speeds, either.

Thank you!

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I know... mine's an E46, I'm just here for the fun (okay, and the navigation-tips)

Time to upgrade again

Current OS disc is V31, which contains 4-1/100 for the Mk4

You sound like you have 4-1/80, which is 2 versions old.

I intentionally went with V.28, because I had the software for burning the ISO at hand. I was a bit nervous about upgrading in the first place, horror stories and all, so I didn't also want to deal with new ISO-software.
In the end, the upgrade went smooth, so I might take the plunge with V.31, but... do I really need to? Are there essential functions or fixes in V.31 I will need to be able to read the new DVD-maps?

I ask because I usually live by the rule "If it ain't broke, don't fix it"... and V.28 seems to work for me.

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I know... mine's an E46, I'm just here for the fun (okay, and the navigation-tips)

That's exactly what 4-1/100 provides: the ability to read dual-layer DVDs, and the 2008-2 Europe DVD is a dual-layer DVD.