Yes, you can assign two rams to XMP1 and the other two to XMP3 profiles.
Yes, you can assign two rams to XMP1 and the other two to XMP3 profiles.
Consider Kingston parts KF548C38BBK2-32 and KF556C40BBK2-32. It’s possible to purchase more KF556C40BBK2-32 at a low cost, though performance results are uncertain. Running them together on a 4800MHz CL38 with [email protected] could work, but expect variable outcomes.
It's roughly 50/50 that these sticks are different, and because of that will have a hard time running in the same system. There really isn't a way around that, either you get lucky and it should in theory work, or you don't and you're left with sets of sticks that either won't boot or won't boot above ~4000MT/s when in the same system. Messing with timings doesn't fix that.