I'm running a fairly substantial SSIS package against SQL 2008 - and I'm getting the same results both in my dev environment (Win7-x64 + SQL-x64-Developer) and the production environment (Server 2008 x64 + SQL Std x64).

The symptom is that initial data loading screams at between 50K - 500K records per second, but after a few minutes the speed drops off dramatically and eventually crawls embarrasingly slowly. The database is in Simple recovery model, the target tables are empty, and all of the prerequisites for minimally logged bulk inserts are being met. The data flow is a simple load from a RAW input file to a schema-matched table (i.e. no complex transforms of data, no sorting, no lookups, no SCDs, etc.)

The problem has the following qualities and resiliences:

1. Problem persists no matter what the target table is.
2. RAM usage is lowish (45%) - there's plenty of spare RAM available for SSIS buffers or SQL Server to use.
3. Perfmon shows buffers are not spooling, disk response times are normal, disk availability is high.
4. CPU usage is low (hovers around 25% shared between sqlserver.exe and DtsDebugHost.exe)
5. Disk activity primarily on TempDB.mdf, but I/O is very low (< 600 Kb/s)
6. OLE DB destination and SQL Server Destination both exhibit this problem.

To sum it up, I expect either disk, CPU or RAM to be exhausted before the package slows down, but instead its as if the SSIS package is taking an afternoon nap. SQL server remains responsive to other queries, and I can't find any performance counters or logged events that betray the cause of the problem.

I'll gratefully reward any reasonable answers / suggestions.