I will be specific about everything, so I recommend reading the specs carefully and then replying with your ideal and logical answer.
The problem is: Windows 7 Ultimate 64bit's Resource Monitor shows 778 MB of RAM out of 4096 MB being hardware reserved. I am a user of virtual machines, thus I am in need of using even those 778MB. I am using a Pentium 4 3.0GHz 630 Prescott with motherboard's chipset Intel 945GZ Express which uses Intel GMA 950. As per the configurations given on Intel's website and listed on my system properties, I can come to a conclusion that the Intel GMA 950 which has a default 8 MB RAM is using my system RAM to increase itself to 256 MB. But the remaining 522 MB RAM's usage is confusing me. I cannot seem to find another hardware which might be consuming the remaining 522 MB RAM.
By googling I found some people saying that the chipset is the culprit, and the some saying that sound hardware also consumes RAM. Some people showed some tricks like deactivating the msconfig->boot->advanced->(uncheck) maximum memory. But these were not altered in my system. Some people say that an option for memory mapping in the BIOS will fix the problem, but my BIOS settings do not have any memory related settings.
Now what I am clear about is that if I add a graphic card with RAM=>256 to my system's only PCIe x16 V1 slot, then I can save 256MB RAM. But what about the remaining 522MB?
Please help me with this problem.