Memory module in memory slot not usable
I have a Sony VPC-F113FX/B and it comes with 6GB (1x4GB + 1x2GB) DDR3-666 memory modules. So I have noticed the following problem for quite some time: the memory slot #1 recognizes its memory module but its memory is not made available to the OS.
It is NOT an OS related issue because I have already tested in Linux, Windows and MemTest. None is capable of using the memory module which sits on slot #1.
Yes, of course I have done rotation tests, meaning that both 4GB module and the 2GB one were put in slot #1. The total memory available varies from 4GB (when 2GB is in slot #1) to 2GB (when 4GB is in slot #1).
However, I can access SPD information of BOTH memory modules using CPU-Z, Aida64, MemTest and the BIOS itself.
The graphics card is off-board, so I don't think it is interfering with the total memory available.
I have quite an experience in reworking PCBs, is there any possibility it is just a solder joint problem of the DIMM slot? I have been considering heating it with some hot air, but would not like to risk it if it is obvious a memory controller failure has occurred.
Is this a good question?