Re: [SOLVED] Is my processor 32-bit or 64-bit?
On Tue, Aug 28, 2012 at 1:34 AM, Bob Proulx <bob@proulx.com> wrote:
> Stephen Powell wrote:
>> By the way, there's something I don't understand. A 32-bit processor can
>> only access 4G of "real" (extended) memory, right? So why are there
>> motherboards available for 32-bit processors that support installing
>> more than 4G of RAM? What good is memory that the processor can't address?
>
> With PAE (physical address extensions) the processor *can* address
> more than 4G of ram. A single process is still limited to 32-bits
> which usually works out effectively to 3G of ram but the operating
> system can make use of more than this. It can be used for filesystem
> buffer cache and for multiple 3G programs. A machine with 6G of ram
> for example could run two 3G program at the same time and hold them
> both in memory without swapping. Or run one 3G program and still have
> 3G for the system to use in filesystem buffer cache. With PAE having
> more than 4G of memory is quite useful.
>
> Using PAE does have a small performance impact. It slows things down
> by 2%-3% in my use cases. But the increase in ram for buffers usually
> more than makes up for the differences.
>
iirc, pae is only 48 bits too.
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