I have used both, The p.4 is a better bios than the p.5 both will work though. So you will need either a retail x99 Haswell chip or know some one that can lend you oneWOW! Looks like you have exactly the same CPU as i am, even the A1 revision! Well, it is MSI x99 raider then
Do you have a P.5 Bios or P.4?
Unfortunately, i am not even near houston texas, but thanks anyways!