Vista SP1 Won't Resolve the 4 GB RAM Limitation of 32-bit Windows Vista
section: windows, for your questions: KezNews forum, 4.1.2008
32-bit Windows operating systems, and Windows Vista makes no exception whatsoever to this rule, are limited in terms of the amount of system memory that can be addressed to no more than 4 GB.
But, the fact of the matter is that 32-bit Windows XP or Windows Vista will not use more than 3.2 GB to a maximum of 3.5 GB of RAM, even if the hardware configuration comes with a full 4 GB. This issue does not impact 64-bit Windows operating systems, and with Vista you can go all out when it comes to RAM, as the Ultimate, Business and Enterprise SKUs can support a maximum of 128 GB of physical system memory, while the Home Premium and Home Basic editions will permit the implementation of 16 GB, and respectively 8 GB of RAM.
With Windows Vista SP1, currently planned for the first quarter of 2008, Microsoft will force the operating system to show the full amount of system memory installed, and not only the memory that Vista has available. The Redmond company warned that the change will ultimately depend on the integration with the machine's BIOS and, as such, not all Vista users will experience it. But, it does not mean that Vista SP1 will resolve the 4 GB of RAM limitations of the 32-bit Vista operating system. In this context, if you have a 32-bit copy of Vista, there is no point waiting for SP1 to enjoy up to four GB of RAM, the simplest solution is to go 64-bit.
"Due to an architectural decision made long ago, if you have 4GB of physical RAM installed, Windows is only able to report a portion of the physical 4GB of RAM (ranges from ~2.75GB to 3.5GB depending on the devices installed, motherboard's chipset & BIOS). This behavior is due to 'memory mapped IO reservations'. Those reservations overlay the physical address space and mask out those physical addresses so that they cannot be used for working memory. Significant chunks of address space below 4GB (the highest address accessible via 32-bit) get reserved for use by system hardware: BIOS – including ACPI and legacy video support; PCI bus including bridges etc. PCI Express support will reserve at least 256MB, up to 768MB depending on graphics card installed memory", explained Hilton Locke, Microsoft Software Test Engineer.
source:
news.softpedia.com
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Comments(16)
why is 4gb needed in the fisrt place ?
interesting that vista 32bit will not allow more than 4gb ram, yet some versions of
windows server 2003 32bit, such as enterprise or data centre editions, support up to 128gb
ram.
i appreciate that these are sever os's, but they are older systems than
vista, all designed and coded by microsoft, and isn't vista built on the server 2003
kernal? surely microsoft could have easily given vista 32bit the same ram capabilities as
its older server 2003 systems. after all, isn't that what advanced technology is all
about - providing software technologies capable of supporting new hardware technologies?
or is it only a matter of making money and hindering the advancement of computer
technology from what it could/should be?
after installing vista sp1 i noticed it sees the full 4gb ram installed. if it were not
for one important device i have that doesn't support 64bit i would be using that instead.
windows server still has these limitations, as it's a limitation of addressing 32 bits,
plus having to address all other computer resources within that address space. the way it
gets round it, is by making use of a certain feature in certain bioses along with a work
around in the server os. this work around (i've forgotten the name of it) but it's much
like how himem.sys and emm386.exe used to work in the dos days by allowing segmentation of
the memory, and hence addressing it twice.
in essence it is like being only
able to run programs in the first 640k of ram, but still being able to store data above
that by using these "tricks".
actually the 4gb limit in 32bit os's problem was solved over 3 years ago by microsoft
themselves, but because they are ass holes they wont put it onto their home os's
lol
32bit oses can only ever address a total of 4gb and that includes all memory besides ram.
i.e. video card, etc.
btw, a 64bit processor can address a total of 128tb
(terabytes) not gigabytes. thats twice the storage capacity of the human brain.
if vista wont take more than 4gb why use it then?
cause xp wont take it
either...just a thought
4gb is a limit of the x86 instruction code to address only a total number of 4gb of
memory address space. this has been a problem now since x86 instruction code has been
around for decades, this is not a vista problem. and as for the server os's that support
above 4gb, that is done by way of pae, and even thought it shows more then 4gb, none of
the applications will use above 4gb unless they are specifically written to take advantage
of it using pae. so they can't just add it to xp or vista, every application would have
to be re-written to make a difference..
educate yourselves before you post
ignorant comments.
re: just.. wow
pae! that was the wording i forgot, nice one thanks :)
the actual real problem is that we cant all switch to 64 bit easily. microsoft has forced
us to only install certified drivers on 64 bit. a lot of hardware is not always certified.
another money grab from microsoft. we should at least have the option...
have a new crack dfor vista sp1?
the 4gb addressability issue affects all 32 os's, not just windows. it's further
compounded by x86 architecture requiring hardware addresses be mapped within the
addressable memory space so the hardware can be talked to (not just the hardware, but any
memory on the hardware...e.g. video memory). the reason people commonly put some
arbitrary number below 4gb (such as 3.5gb or 3.1gb) is because they don't understand
what's happening - that's usually the amount of ram available after video memory (and
all other hardware address space) is subtracted - 32bit os's can address all 4gb. there
are some tricks to get around the 4gb boundary with 32bit addressing, and windows is
already capable of it - but, just like many people thought readyboost was just like adding
ram (not even close), this is greatly misunderstood. the address extensions that can be
used don't act like there's suddenly the ability to address more ram - it works somewhat
like emm386.exe worked in ms-dos - bits of usually inaccessible memory can be addressed
and mapped into an addressable page area and written to/read from, then mapped out again -
there are, however, quite a few limitations.
the certified drivers issue with
vista64 has nothing whatsoever to do with a money grab - you do have at least two options
around that issue in x64. i'm not trying to flame you, but instead of complaining, do a
little searching - the answers are out there. the certified driver requirement is one of
ms' attempts to have some control over the quality of drivers loaded by the os so people
will have a more stable os experience and quit whining about how unstable windows is when
quite often it's due to crappy hardware, drivers, or other software. the major reason
macs are so 'reliable' is due to apple's anal level of control over most things - and
even they still crash occasionally, have security holes, etc.
there are
***plenty*** of valid reasons to bitch about ms - but driver signing requirements and the
32bit addressability limit really don't fit into that category, imo.
wonder how people type that much lol
notsomeoneelse is right on and nobody is forcing you to install unsigned driver in x64
version vista. you can always turn off the signed driver requirement. (just search it in
google). to be honest, if a hardware vendor didn't bother to get their driver and
hardware certified, it's a good sign that they have a crappy support and you shouldn't
use their hardware at the very first place.
this article is complete bs.
vista 32 supports pae on some hardware. google for vista pae or visit:
http://www.thegeeksweek.com/blog/enabling-pae-on-32-bit-windows-vista.html
and
http://www.microsoft.com/whdc/system/platform/server/pae/pae_os.mspx
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Why use 4GB
By xavier on 05.01.2008 - 06:01