Vista 64 and Memory

Daveyboyuk

Daveyboyuk

Daveyboyuk

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Joined
23 Nov 2007
Posts
106
Hey guys,

This maybe a stupid Q, but I have seen a few people posting that they need Vista 64 because they have 4gb of memory. Why is this? I though Vista 32 could address 4gb and that is the physical limit for 32bit systems. Why would running a 64bit OS on a 32bit system make a difference?

Thanks
Dave
 
Windows XP and Windows Vista 32-bit will only be able to address around 3GB of RAM. The only way you will be able to address and use all of the 4GB of memory is, if you purchase a 64-bit Operating System weather that be Windows XP or Windows Vista. If you are looking at buying a 64-bit Operating System and worried about the compatibility side of things, the support really is superb now and the majority of the manufactures out there have released 64-bit drivers for their hardware. :)
 
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Another difference, is that 32bit windows will only ever assign a maximum of 2GB of memory to a single application, unless that application is written with PAE support. 64bit windows on the other hand can give a single application all 'free' memory if required.

So if you run a single memory hog application then 64bit is for you. But if you multitask and fill your ram with a large number of applications then 32bit 'can' make use of 3gb or so memory. 64bit is still better though, as the 4GB is all addressable memory, not just the main ram. This includes framebuffers on graphics cards, various expansion cards can contain memory. Also little things like System Bios/Roms etc all are sitting in there.
 
Something else that may interest you is that while a 32bit OS can only address up to 3 - 3.5GB of RAM, a 64bit OS can address up to 16,000,000,000GB of RAM. Small difference :p
 
Cool cheers guys. So physically a 32-bit system can address upto 4gb system memory + sound/graphics memory, but 32-bit windows can only address 4gb system memory - sound/graphics memory?

Considering Vista 64 now....
 
"Processors capable of referencing larger address spaces provide the opportunity to use more physical memory than ever before, potentially reducing the overhead spent moving processes in and out of physical memory. The 64-bit processors are theoretically capable of referencing 2^64 locations in memory, or 16 exabytes, which is more than 4 billion times the number of memory locations 32-bit processors can reference. However, all 64-bit versions of Microsoft operating systems currently impose a 16 TB limit on address space and allow no more than 128 GB of physical memory due to the impracticality of having 16 TB of RAM. Processes created on Windows Vista x64 Edition are allotted 8 TB in virtual memory for user processes and 8 TB for kernel processes to create a virtual memory of 16 TB."
 
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