i have an msi 6728 intel 865pe neo 2p motherboard with an intel p4
im curious how to use the 4gb which both intel and msi claim the processor an motherboard support i have tried to install vista 64bit on th e motherboard thinking that a 64bit operating system was required to access more than 3½gb of ram under xp32bit however the os failed to install i assume this is because teh p4 is 32bit processor
here si the text from the chipset description and the picture is the diagram associated with the 865pe
it seems a shame that on top of the lost ½gb of ram i loose a further 2gb if i had an agp vga cardwith 1gb of ram on it + any further loss of ram when five more pci vga interfaces are connected
couldnt the piece of ram that windows xp 32 bit cant access be used by the agp aperture or pci vga devices would this require a new bios upgrade or is something more substantial required?
System Address Map 4 A processor system based on the 865PE/865P chipset supports 4 GB of addressable memory space and 64 KB+3 of addressable I/O space. There is a programmable memory address space under the 1-MB region that is divided into regions that can be individually controlled with programmable attributes such as disable, read/write, write only, or read only. Attribute programming is described in Chapter3. This section focuses on how the memory space is partitioned and the use of the separate memory regions. The Pentium 4 processor with 512-KB L2 cache on 0.13 micron process in a 478-pin package processor family and the Pentium 4 processor 90 nm process support addressing of memory ranges larger than 4 GB. The MCH claims any processor access over 4 GB and terminates the transaction without forwarding it to the hub interface or AGP (discarding the data terminates writes). For reads, the MCH returns all zeros on the host bus. Note that the 865PE/865P chipset platform does not support the PCI Dual Address Cycle Mechanism; therefore, the platform does not allow addressing of greater than 4 GB on either the hub interface or AGP interface. In the following sections, it is assumed that all of the compatibility memory ranges reside on the hub interface/PCI. The exception to this rule is VGA ranges, that may be mapped to AGP. In the absence of more specific references, cycle descriptions referencing PCI should be interpreted as the hub interface/PCI, while cycle descriptions referencing AGP are related to the AGP bus. The 865PE/865P chipset memory map includes a number of programmable ranges. Note: All of these ranges must be unique and non-overlapping. There are no hardware interlocks to prevent problems in the case of overlapping ranges. Accesses to overlapped ranges may produce indeterminate results. 4.1System Memory Address Ranges The MCH provides a maximum system memory address decode space of 4 GB. The MCH does not remap APIC memory space. The MCH does not limit system memory space in hardware. It is the BIOS or system designers responsibility to limit memory population so that adequate PCI, AGP, High BIOS, and APIC memory space can be allocated. Figure10 provides a simplified system memory address map. Figure11 provides additional details on mapping specific memory regions as defined and supported by the MCH