RAM problem with motherboard P5B

**KAITLIN** · 29-01-2009

I have just set up a Core2duo E6400 on an Asus P5B. I install 4 sticks of 1gb RAM and everything else and I start BIOS detects only 3gb RAM instead of 4. I installed on a M2N-E of a friend and found the bios 4gb.

Can some know why my motherboard not recognize 4gb RAM ?

**KADEN** · 29-01-2009

To see 4gb of ram, 32-bit versions of different windows (xp or vista) can only see 3GB, but 4 GB used for functions that are outperforming us.

**EDRIC** · 29-01-2009

Your cards, ports and other inputs / outputs take a piece of the address space of the processor (32 bits = 4GB) Outside you can not have and memory and input-output to the same address range.
So do you eat a piece of ram not usable.