Memory slot doesn't work

Tomer Vaknin

Honorable
Apr 21, 2014
10
0
10,510
Hey.
This problem started long time ago, but I didn't succeed to solve it.
I decided to try again, maybe I missed something.
Motherboard: Intel DH55PJ

One of the slots doesn't work, but the stick is recognized (I'm sure that the problem is with the slot and not with the sticks).
It means that memtest recognize the 2 sticks (transcend and Samsung 2gb each), but only get 1981mb of RAM.
I remember that sometimes the bios recognized both and sometimes it didn't, and even few times somehow Windows recognized them but could only use 1.9GB of RAM.

What could possibly gone wrong and what should I do (anything...)?