3

Originally, I had 4GB of RAM (4*1GB), and everything worked like a charm.
A few months ago one of my memory cards got bad, so I had to take it out and throw it away.

A few days ago I bought 2 new identical cards and installed them,
so there are 2*1GB of one manufacturer (kingston), and 2*1GB of another (CEON).
In total it should bring me back to 4GB dual channel.

CPU-Z reports they are all installed (CPU-Z report),
but when BIOS is starting it shows 3145728K, and windows also recognizes only 3GB (system information).

So... Where's the problem?

Dimdum
  • 139

1 Answers1

-2

Due to an architectural decision made long ago, if you have 4GB of physical RAM installed, Windows is only able to report a portion of the physical 4GB of RAM (ranges from ~2.75GB to 3.5GB depending on the devices installed, motherboard's chipset & BIOS).

This behavior is due to "memory mapped IO reservations". Those reservations overlay the physical address space and mask out those physical addresses so that they cannot be used for working memory. This is independent of the OS running on the machine.

Quoted from: http://blogs.msdn.com/b/hiltonl/archive/2007/04/13/the-3gb-not-4gb-ram-problem.aspx

From the CPUZ factsheet, the mobo is i945. Read more: https://forum-en.msi.com/index.php?topic=123711.0

In simple words: Or, a Windows 64-bit computer may show only 7.1 GB of usable system memory when 8 GB of memory may be installed. This is because usable memory is a calculated amount of the total physical memory minus “hardware reserved” memory. http://www.thewindowsclub.com/computer-ram-graphics-card-video-memory

Gaurav Joseph
  • 1,783