If we are not pantheists (in which all is god) than God is discrete from that which is not God. He knows that which is Himself and that which is not. And given those two realms of that which is (God and not-God), the referent of a point of knowledge which God possesses can be spoken of as being either Actual or Conceptual. That which is Actual has a referent outside of God. It exists and isn't God. That which is Conceptual has a referent inside of God (a mental construct as memory or anticipation would be) and it has no non-God actuality.
When the question of God's foreknowledge (or past-knowledge for that matter) arises, these two categories do as well. Is God outside of Time looking down on Actualities? Or is Time not in question at all because God's knowledge of the future (or the past) is Conceptual? I mention the past, for so many wish to create a special sphere of atemporality in which God might dwell without examining whether or not they are talking nonsense. If God is looking down on Time from an atemporal vantage then those things observed are Actual and existent. Christ is still on the cross (for God) and always was (for God) and will be forevermore. The Trinity can never be fully united for those words of Christ, "My God, My God, why have you forsaken me?" will ring in actual existence for God, forever. Amen? That or the knowledge of God regarding the past is Conceptual (just like your memories) and He "remembers" what was, not sees what was but saw. Maybe, dare I suggest it, that God's knowledge of the Future is equivalently Conceptual? In fact, the Death of Christ on the cross is burdensome for Future thought as well as Past. Why, you ask? The Trinity of God,(atemporal and dealing with Actualities), has been eternally lacking in Triuneness since He has been eternally in a knowledge relationship with everything that is Actual and that Actual, (because Actual) binds and defines the content of truth of the thing known. So the Actual crucified state of Jesus is and was and will be (from our temporal vantage and language) the state of God. And to add insult to the injury of this silly talk of Time, God's relationship with Himself in the Trinity is also known and enjoyed as united for there have been "Times" when the atemporal God looked down on Actual non-separation AND rejoiced in the Tiune presence of the Conceptual knowledge of Himself, fully and truly united. So... Actual separation and Actual non-separation both being true for God in the same "God-moment" regarding the same characters. Looks like you either have to throw out the "Universal Law of Non-Contradiction (A cannot be non-A) or throw out Time.
It is actually a choice between you being able to "know" anything because you have made statements which call laws of Logic into question or you reject a dimension called Time. It was cute when you didn't think about it too much.
And if you are a Calvinist, God help you, but you didn't need Time in the first place. Your benighted definition of God has His foreknowledge resting in the Decree, not foresight and atemporality.