You are correct in having to choose the ACE provider for x64 bits.
And the big advantage of JET was it was (and still is) installed on all copies of windows by default. So no need to install Access or the runtime, or previous the office connectivity package.
As for performance? There has been a few comments about performance in regards to ACE x64.
However, one trick or suggestion is to ensure that the connection stays open. In other words, are you sure the row processing is going slow, or it is the overall time?
(perhaps put a test msg box, or test in your code.
Eg:
Dim T as single
T = timer()
‘ your code here
Debug.print timer() – t
The above will thus spit out the time to the debug window (while in VBA ide hit ctrl-g to display the immediate/debug window.
The reason why I suggest force open idea is often you find that ACE takes a VERY long time to open. But once open then the data reading has good performance (same as before).
So, I suggest to check and try this fix.
So open a table (any table) and KEEP it open. Now run your existing code (that may well open + close other tables). The issue is when ACE attempts to open a table, it tries to put locks on the mdb/accdb file and it is this process that takes VERY VERY long time.
However, if you force (keep) open one table, then this VERY slow process of ACE attempting to lock the file for read/write does not occur each time you execute a query, or create additional recordsets in code.
So, if the row reading speed is fast, but the time to START + open is very slow, then before you run + test your routines, force open a table to some reocrdset (keep it active and in scope), and THEN try your code.
I find 9 out of 10 times, this results in elimination of this slow speed, and often I seen the results are nothing short of spectacular (it will run faster then before!!!)