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Thread ID: 98904	2009-04-12 07:23:00	Maximum RAM for XP	convair (13650)	Press F1

Post ID	Timestamp	Content	User
764222	2009-04-13 23:04:00	Thats because you have a 512MB Graphics Card ;) Wouldn't that be the graphics is built in?	convair (13650)
764223	2009-04-13 23:13:00	To answer the 3.5GB limit question...... Remember that in the absence of the 64 bit support, the Windows memory manager is limited to a 4GB physical address space. Most of that address space is filled with RAM, but not all of it. Memory-mapped devices (such as your video card) will use some of that physical address space, as will the BIOS ROMs. After all the non-memory devices have had their say, there will be less than 4GB of address space available for RAM below the 4GB physical address boundary. the motherboard assigned the ROMs and the hardware devices to the physical address space between 3.5GB and 4GB (occupying about 0.5GB of address space). When you start plugging in your memory chips, then, they are assigned physical addresses starting at the bottom, and then skip over the address space that has already been assigned to the hardware and ROM, then resume. On this imaginary system, then, the 0.5GB of address space used for hardware and ROMs causes that much memory to get shoved upwards, and it ends up above the 4GB boundary. Without 64 bit support, the processor is capable only of addressing memory below the 4GB boundary, which means that the memory above that boundary is inaccessible. It's consuming electricity but isn't doing anything. The solution is to go to 64-bit OS so that the processor can access the physical address space above the 4GB boundary. So why don't we just map the ROMs and the hardware devices to space above 4GB?? then the CPU can't access the IO devices so you have system with 4GB of RAM and no video card...... any questions??	robsonde (120)
764224	2009-04-13 23:59:00	Wouldn't that be the graphics is built in? Nope, video RAM shares the same 4GB limit as system RAM. Its the combination of both that is 4GB, so if you have a 256MB Graphics Card, you'll technically be seeing around 3.7GB in Windows of physical RAM	Chilling_Silence (9)
764225	2009-04-18 13:09:00	Why would anyone need 128Gb of RAM for a typical desktop workstation? - just wondering since that is a ton To some one from 1980 who would have ~640k of RAM, todays 3gB would seem monstrous,or perhaps even sick or depraved! I quite enjoy downgrading while everyone else is upgrading-and not spending any money! www.google.co.nz %2F26%2Fone-week-at-100mhz-x-less-and-not-a-hiccup%2F&ei=58LpSb-cGIf6kAXom5mtCA&usg=AFQjCNFzM17n4J_7eJsGfdGNGK2p2br6Rw&sig2=sP24lsaDEfnIzbyqUYnk5A	pkm (13527)
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