Sql Script takes much longer than estimated In order to clean up a very large table holding binary Files in IMAGE Cols, I created the following sequence (based on this: Article) to get rid of a part of those image Blobs quickly:


Select * into temp table where (filtering a small part I want to keep) 
Select the rest of rows WITH a NULL value for the BLOB into same temp table.
Truncate the original blob table
copy all records back from the temp table to the original table.


I did a test run on a local machine (notebook) and Step No. one took about 20 seconds for about 2 Milion records.

The whole script took about 4 minutes while the original table held about 2.5 Milion REcords.

In a staging server env. step No. one meanwhile takes > 25 Minutes to copy 3.2 Million records!!! And SSMS actually stopped interacting with me. I estimated (using calc.exe) it might take about 1 Minute...

Now I wonder what is wrong...?

TY
I figured it was the Revovery Model that was left set to FULL. As the article linked in the question says,  it is required to change it to simple of bulk: "The recovery model SIMPLE and BULK_LOGGED perform "best" contrary to the recovery model FULL." 
So, after setting it to simple the process performed within couple of minutes.