...and be patient
I don't think this alone will improve performance much because in my opinion the most time consuming step is read and write from and to the L2 data store and not from and to the L2 address tag.
As soon as I am finished with optimisation, I will make a benchmark run even if I don't attach much importance to this.
However, before I do this I also like to try changing some other settings of the northbridge. For that purpose, it would be helpful to have a screenshot of the Asus P5A Rev. 1.04 and Rev. 1.06 settings as shown by WPCRedit 1.4 like I did it above.
So, if anyone here owns that board in one of these revisions, please take time for this shoot.
Closest I have is P5A-B 1.04