Won't boot up with 2 ram but works with only 1 ram

Kaithedestroyer

Reputable
Feb 4, 2016
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4,530
Okay, this is my problem now.
I just finished building my new custom gaming pc and when I turned it on it won't boot up into bios. Fans are spinning and everything but all I got is blank screen. I disassembled everything and unplug any sockets that might cause this. Then I found out it was the ram. I can only get it to boot with just one ram stick.
The thing is, both of my ram stick, which is 4gb each, works fine. But only works on the second slot(A1), while putting it on the first ram slot(B1) won't boot up the computer on either ram stick.
But when I install the second ram stick on the A1 slot while already in windows, CPU-Z detects 8gb of ram installed and the pc works just fine until I restart.
Another thing I did is plugging the second ram at bios then hit F1 and it boot up normally. I check the window system I got 8gb ram installed yet only 4gb usable(but that's another story for now). Like before, everything works just fine until I try restarting it.
Also, my BIOS has no advanced option overclocking the memory and I have no way of configuring the memory setting at all. I'm stuck with one 4gb ram stick and I really want 8gbs of ram.
My motherboard is ASUS M4A78LT PLUS and the bios is already updated to 0502 version which is the most current one.
Is there anything I must do to get this work? Does it have to do with my CPU?