>>I think that the save is going to be significant, but it's up to you to test.
>
>Presently, it takes 0.0156 second for an update to be done. When I multiple that for a batch of 100 records, this takes 1.56 seconds. If a batch update of 100 records can be done in 0.5 seconds for example, that would represent something along a 1 second save for every 100 records representing a saving of about 10000 seconds for 1 million records. That would be a saving of about 3 hours. I have 4 million records to process. If I could reach this target, this would be a saving of about 12 hours. Presently, the entire process is schedule to take 55 hours. So, I could bring it down to 43 hours.

I think if you try to apply passing a batch of, say, 10K updates at a time, you may save about 10 hours. Unfortunately, it's impossible to predict right now the exact save time. But I am pretty certain that there should be a significant gain.

If you want to confirm my suggestion, you can ask your question in this forum

https://social.msdn.microsoft.com/Forums/sqlserver/en-US/home?forum=transactsql

There are several high reputable SQL Server MVPs which are frequently present and with luck you can get a good advice.