Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?
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Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?
#2Which myth exactly?
Also, swapping memory in and out of the address space is a rather costly operation. And it becomes infeasible if the process's working set grows larger than the available address space [thrashing].
Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?
#3Did everyone forget about bank switching and address extension tricks like PAE?
Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?
#4Which myth exactly? Also, swapping memory in and out of the address space is a rather costly operation. And it becomes infeasible if the process's working set grows larger than the available address space [thrashing].
I think that on Linux, the 4G/4G split never made it, so in practice the limit is around 64GB due the limited amount of lowmem available to the kernel in the regular 3G/1G split.
Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?
#5There was a myth?
Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?
#6There is also a very recently developed middle ground, the Linux "x32" ABI, since Linux v3.4: http://en.wikipedia.org/wiki/X32_ABI
As I understand it, this mode gains performance by sticking with 32bit pointers in user-space instead of 64bit pointers, while still allowing for taking advantage of all the new registers etc available in x86-64 ("amd64") CPUs. (Many programs doesn't really need more than 4gb virtual address space, and so using full 64bit pointers can cause quite the overhead - imagine doubly-linked lists with small data structures, for example)
Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?
#7[deleted]
Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?
#8There is also a very recently developed middle ground, the Linux "x32" ABI, since Linux v3.4: http://en.wikipedia.org/wiki/X32_ABI As I understand it, this mode gains performance by sticking with 32bit pointers in user-space instead of 64bit pointers, while still allowing for taking advantage of all the new registers etc available in x86-64 ("amd64") CPUs. (Many programs doesn't really need more than 4gb virtual addr…
x32 is clearly a good technical solution. If you're running on a 64 bit kernel, x32 is superior to i686 in every measurable way.
But it's also yet another architecture. It's not binary compatible with either i686 or x86_64. You need your whole userspace compiled to use it. Middleware with embedded assembly (there's a surprising amount of this in glibc, and of course things like ffmpeg, libjpeg, etc...) needs to be ported. You can't run 32 bit binaries from proprietary sources.
And frankly the benefit over straight x86_64 is quite modest. I don't see x32 taking off. It's just not worth the hassle.
Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?
#9Am I missing something, or does the top answer not address the question? Memory tricks aside, it seems the questioner is asking whether the physical RAM itself will ever be used. Short of PAE, unless my understanding is wrong, I was under the impression that the answer to this is no.
Re: Can a 32-bit OS machine use up all 8GB RAM + 20GB page file?
#10Stop editorialising with titles