You can speed up offline servicing for WIM with SCCM by removing indexes from the WIM. The system compares processing to a series of indexes, each written for a specific scenario. You won’t need all of those indexes for your specific deployment. View the indexes with the command
dism /get-imageinfo /imagefile:E:Install.wim
Remove unnecessary indexes one by one with the command
dism /delete-image /imagefile:E:Install.wim /index:1
— the above example would remove index 1, change the index number in the command according to your selection.
The index number resequences with the removal of each index. Requery after each index removal to see the new number of the next index you want to remove. Fewer indexes listed in the WIM will shorten the offline servicing time.