32bit OS-ovi mogu da adresiraju maksimalno 4GB memorije. 4GB UKUPNO, gde spada i Video memorija, BIOS, RAM .. u praksi, to znači (u zavisnosti od grafičke kartice) da ostaje oko 3.2 GB memorije, bez obzira koliko "nagurate" u računar.
Ali da se ne pravim previše pametan, evo šta na tu temu kažu oni koji su napisali te "prozore", mada nisu zapravo oni krivi, već 32bita :)
"Various devices in a typical computer require memory-mapped access. This is known as memory-mapped I/O (MMIO). For the MMIO space to be available to 32-bit operating systems, the MMIO space must reside within the first 4 GB of address space.
For example, if you have a video card that has 256 MB of onboard memory, that memory must be mapped within the first 4 GB of address space. If 4 GB of system memory is already installed, part of that address space must be reserved by the graphics memory mapping. Graphics memory mapping overwrites a part of the system memory. These conditions reduce the total amount of system memory that is available to the operating system.
The reduction in available system memory depends on the devices that are installed in the computer. However, to avoid potential driver compatibility issues, the 32-bit versions of Windows Vista limit the total available memory to 3.12 GB. See the "More information" section for information about potential driver compatibility issues.
If a computer has many installed devices, the available memory may be reduced to 3 GB or less. However, the maximum memory available in 32-bit versions of Windows Vista is typically 3.12 GB."
a kompletan tekst je dostupan na Microsoft strani, ovde:
http://support.microsoft.com/kb/929605
Naravno, to je jedna od stvari koju znaju svi proizvodjači Hardware-a, čak i ovi naši domaći, ali eto, nisu ni oni krivi, krivi smo mi potrošači koji stalno traže brže, više, bolje, ... pa kad nema više, onda ... mora malo marketing da radi da bude više.