Is it wrong to consider SCAN DENSITY as a performance metric in higher versions of SQL Server apart from SQL Server 2000?
Scan Density is how many times you jump from one extent to another (dividing the &quot;optimal&quot; to the current state). Thing is that this is a side effect of logical fragmentation (jump back and forth between pages, and you are likely to jump back and forth between extents). When the DBCC was redone into a DMV, Paul cleaned up lots of stuff in there.
I suggest you work with logical frag instead (avg frag in percent), if you care about how contiguous things are in the first place. Perhaps more interesting is how full pages are, since random vs seqential I/O is probably more or less irrelevant with modern hardware (read-ahead set aside).
Paul vocals pretty strongly how we should stop using the old DBCC and use the DMV instead.  Do some searches and you will find lots of good nuggets out there. Here is one thread that can give you some insights, for instance: https://social.microsoft.com/Forums/partner/en-US/8d01a374-1493-43c3-8cea-5bf5de723b4d/dmdbindexphysicalstats-and-dbcc-showcontig-disparity.