Anton, yes, even though you have a memory ram on your video card, for faster access, on 32 bit systems it is MAPPED, not put in RAM, to the upper RAM Address available to the OS. Once MAPPED, that memory is NO LONGER available to the OS. So, between the BIOS re-mapping, Video re-mapping, and other device re-mapping, you are generally going to have the OS see 3.2 GB's or less on 32 bit OS's with 4 GB's of memory (or more which it can't see at all) installed.
From the last link I gave you :
Since only a maximum of 4GB virtual memory address range is available in Windows Vista, which are sub-divided or allocated some memory address range to manage both the computer’s PCI memory address range (also known as MMIO) which used for system video graphics cards, BIOS, IO cards, networking, PCI hubs, bus bridges, PCI-Express, and RAM, so the amount of available RAM is always less than 4 GB. BIOS takes up about 512 KB, with video or graphic accelerator card needs memory address for at least the amount of memory on the graphics card. Which mean if you have 256 MB VRAM graphic card, at least 256 MB already been used up from your 4 GB memory available to Windows Vista. The net result is that a high performance x86-based computer may allocate 512 MB to more than 1 GB for the PCI memory address range before any RAM (physical user memory) addresses are allocated. So the typical available RAM for the OS will be reduced to between 3 GB and 3.4 GB.
Understand what the above says, 1/2 GB for BIOS, 1/2 GB for Video card, and I quote from the above, "so the amount of available RAM is always less than 4 GB. BIOS takes up about 512 KB, with video or graphic accelerator card needs memory address for at least the amount of memory on the graphics card.".
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Posted 6 years ago