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Message: <blockquote data-quote="azhrei_fje" data-source="post: 4666078" data-attributes="member: 12966">Well, then I have a clarification for item #2. <img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f642.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":)" title="Smile    :)"  data-smilie="1"data-shortname=":)" />This is a limitation of the operating system, and not necessarily the hardware.  It depends on how the address lines are attached to the MMU.The MMU can be programmed to allow certain logical addresses (those that the CPU is manipulating; sometimes called effective addresses, too) to become physical addresses on the address bus, perhaps with some trickery to modify the top few bits.  But this does not require that the real system RAM in those locations be wasted!In fact, the OS could remap lower logical addresses via the MMU so that said address was in the bottom 2GB (for example) and the physical RAM address was in the area being shadowed by the video RAM.It's entirely possible that Windows doesn't bother with this optimization due to the variety of hardware it must support and it just wastes your RAM, but other operating systems (think Unix and Linux) will make use of all physical RAM in the machine, assuming the hardware is capable of it.  In other words, there is no hardware implementation limit that says video RAM must replace system RAM; this is a system design constraint.Now on the really low-end hardware, your video RAM might be extremely small (like 32MB or something) and that memory is only used at boot time.  Once the OS is running it allocates system RAM to act as video memory and programs the video card to retrieve its data from there.  This is generally much slower, though, and that's why the high-end video cards come with 256MB or 512MB of on-board RAM.  By having on-board RAM, the video card can be accessing its memory while the CPU is accessing its memory and there's no contention for the system bus. I've got an old POS eMachines that does this.  (But hey, my final cost for the 64-bit box was $300 back in 2004, so I'm not complaining. <img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f642.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":)" title="Smile    :)"  data-smilie="1"data-shortname=":)" />)</blockquote>

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