Augustinianism is not nearly as specific as 5-points, Dordt Calvinism. For instance, I don't know of anyplace where Augustine specifically addresses limited atonement.
The largest difference is that Augustine held to single predestination (God chooses the elect, but does not actively reprobate anyone - he simply "passes over" them), while Calvin held to double predestination (God choose the elect to salvation, and the reprobate to damnation).
Here are some specific quotes of Augustine's, as they relate to some of the points of Calvinism:
On The Predestination of the Saints, ch. 11
Therefore the election obtained what it obtained gratuitously; there
preceded none of those things which they might first give, and it
should be given to them again. He saved them for nothing. But to the
rest who were blinded, as is there plainly declared, it was done in
On The Predestination of the Saints, ch. 16
Faith, then, as well in its beginning as in its completion, is God’s
gift; and let no one have any doubt whatever, unless he desires to
resist the plainest sacred writings, that this gift is given to some,
while to some it is not given. But why it is not given to all ought
not to disturb the believer, who believes that from one all have gone
into a condemnation, which undoubtedly is most righteous; so that even
if none were delivered therefrom, there would be no just cause for
finding fault with God.
Enchuridion ch. 25
Furthermore, who would be so impiously foolish as to say that God
cannot turn the evil wills of men—as he willeth, when he willeth, and
where he willeth—toward the good? But, when he acteth, he acteth
through mercy; when he doth not act, it is through justice. For, "he
hath mercy on whom he willeth; and whom he willeth, he hardeneth."
On The Predestination of the Saints, Ch. 13
This grace, therefore, which is hiddenly bestowed in human hearts by
the Divine gift, is rejected by no hard heart, because it is given for
the sake of first taking away the hardness of the heart.
Perseverence of the Saints
On The Predestination of the Saints, ch. 33
For all who are teachable of God come to the Son because they have
heard and learned from the Father through the Son, who most clearly
says, “Every one who has heard of the Father, and has learned, cometh
unto me.” But of such as these none perishes,
because “of all that the Father hath given Him, He will lose
none.” Whoever, therefore, is of these does
not perish at all; nor was any who perishes ever of these.
Single vs. Double Predestination
Look at the quotes under "unconditional election" above. Augustine speaks passively about the non-elect. God witholds the grace of election, but is not actively reprobating. Contrast this with Calvin on reprobation:
At last, he concludes that God has mercy on whom he will have mercy,
and whom he will he hardeneth (Rom. 9:18). You see how he refers both
to the mere pleasure of God. Therefore, if we cannot assign any reason
for his bestowing mercy on his people, but just that it so pleases
him, neither can we have any reason for his reprobating others but his