SQL Select top 1 record on dm_db_index_physical_stats with a join on sys.partitions very slow

I'm running a small query below in a MS Dynamics AX 2012 database and it runs more than 5 minutes which I had to cancel and it is showing PAGEIOLATCH_SH wait type. The database data file is 560GB and on SQL Server 2012 SP1.

SELECT TOP 1 A.avg_fragmentation_in_percent
FROM sys.dm_db_index_physical_stats(DB_ID(),NULL,NULL,NULL,NULL) A 
INNER JOIN sys.objects B
ON A.object_id = B.object_id
INNER JOIN sys.indexes C 
ON B.object_id = C.object_id AND A.index_id = C.index_id
INNER JOIN sys.partitions D 
ON B.object_id = D.object_id AND A.index_id = D.index_id

I checked resource monitor in the server for disk activity and the Read(B/sec) shoots up from an initial 23,000 to over 13,000,000 while the query is running and goes back down after the query is canceled.

Any ideas what may be causing this?