Buying a new PC? Don't bother getting more than 3GB of Ram.

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KenOath

Buying a new PC? Don't bother getting more than 3GB of Ram.

Post by KenOath »

Thinking of buying a top-of-the-range Windows Vista PC with loads of Ram? Then just be sure that "loads" is no more than 3GB: you could be throwing away anything from £50 upwards.
Buy a PC with 4GB of Ram, and you can wave goodbye the last gigabyte. The reason is the memory-mapped input-output (MMIO) method - the system by which PCs communicate with installed devices, such as graphics cards.

A computer's internal devices may require their own allocation of Ram to be mapped into the main system Ram. But 32-bit computers, most of which run XP or Vista, are limited to a maximum addressable memory of 4GB.

A machine fitted with, say, a 512MB graphics card must find mapping space for that half-gigabyte in the computer's memory address book - even though the device will use its own memory during operation. However, Ram allocated for device-mapping is not available to applications. This is not a Microsoft-specific quirk; it affects any 32-bit system, including those running Linux.
The problem is that memory-mapping of devices takes place in the addressable area above 2GB, traditionally considered a "safe zone" because consumer PCs tended not to have more memory than this. With the arrival of Vista, though, computer buyers are ramping up their Ram requests.

Paul, a retired senior police officer, says: "I consider myself fairly knowledgeable about computers, but I didn't know about Ram limitations. I bought a 2GB PC and later added more memory. Before doing so I checked the supplier's website and the Ram options went to 4GB - so there appeared no reason not to purchase a further two 1GB sticks. That's where the fun started." Thanks to MMIO, his PC's 512MB graphics card and other devices lopped a gigabyte off what he expected to be 4GB of memory available for applications.

The Guardian has found many PC manufacturers offering upgrades to 4GB. Dell, for example, sells PCs with 32-bit editions of Windows pre-configured with up to 2GB of memory. But the option to go to 4GB is available and would-be buyers are told: "Upgrading your memory is one of the most cost-effective ways to supercharge performance." True, so long as you stop at 3GB.

The Guardian asked Dell why it actively promotes 4GB in machines that can only provide 3GB of usable memory. Dell responded: "Whilst Dell does not call out this restriction on its website it does clearly state the reduction in capacity in its legal birdseed [smallprint] that appears on advertisements."

But Gareth Odgen, editor of Custom PC magazine, says that shoppers should simply not bother with 4GB PCs: "There's not much point putting 4GB in a 32-bit system

Source

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Post by empireum »

This is true for a 32-bit CPU system or a system running a 32-bit OS (which might well have an x64 processor). If you run an x64 OS, this limit does not apply anymore.

KenOath

Post by KenOath »

empireum wrote:This is true for a 32-bit CPU system or a system running a 32-bit OS (which might well have an x64 processor). If you run an x64 OS, this limit does not apply anymore.
Yeah I know 64bit can handle more ram, the post does refer to 32bit
systems throughout the post...
I couldn't add 32bit to the title as I ran out of room to add it...

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Post by empireum »

No problem, I just wanted to add it as a hint.

KenOath

Post by KenOath »

empireum wrote:No problem, I just wanted to add it as a hint.
I wasn't meaning to sound blunt then if that's the way you read it,
I wasn't sure though if you were educating me or adding a sidenote to
the post...
The problem with the topics posted here is you only have 1 line to give
a title with brief explanation...
The IPB forums give 2 lines, 1 for title , 1 for subject which gives plenty
of room for a full explanation...

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Post by nicknowsky »

its true RAM is just going out the window nowadays I feel that 2GB is enough for Vista and OSX

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Post by empireum »

KenOath wrote:
empireum wrote:No problem, I just wanted to add it as a hint.
I wasn't meaning to sound blunt then if that's the way you read it,
I wasn't sure though if you were educating me or adding a sidenote to
the post...
The problem with the topics posted here is you only have 1 line to give
a title with brief explanation...
The IPB forums give 2 lines, 1 for title , 1 for subject which gives plenty
of room for a full explanation...
I only wanted to give a sidenote to the topic because the author of the source completely skipped the option of running an x64 OS.

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Post by spaceship9 »

this windows only??
because my friend has some linux distro running on a x86 Pentium 4 with 4 GB of ram and the distro shows all for gigs...
though fairly pointless because he rarely uses more then 2...
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twermund

Post by twermund »

spaceship9 wrote:this windows only??
because my friend has some linux distro running on a x86 Pentium 4 with 4 GB of ram and the distro shows all for gigs...
though fairly pointless because he rarely uses more then 2...
I have this much in my computer as well, and normally when I use this much RAM is for virtualazation, and it comes in handy quite often when opening programs and things of that sort.

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Post by ppc_digger »

On x86-64, Linux can use up to 64GB of RAM even if you're running it in 32-bit mode. If your system is not 64-bit, you can use up to 4GB (just a few tricks Linux uses if you enable 'high memory' in your kernel configuration), not 3GB as in Windows.

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Post by ___ »

empireum wrote:This is true for a 32-bit CPU system or a system running a 32-bit OS (which might well have an x64 processor). If you run an x64 OS, this limit does not apply anymore.
there is a limit, but rather large (although in a few years or something people will probably get close). weren't there some server versions of windows that could handle more (32bit not 64bit)

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Post by empireum »

Server versions of Windows can of course handle more memory, even on x86, but on special systems that support this. Windows 2000 DataCenter, for example, can handle up to 64GB of RAM.

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Post by atomcomputer »

On Windows 2003 server you can fix it to "theoricly" 64Gb with PAE in the boot.ini.
I've done this on Windows 2003 Buisness 32but on an GX620 Optipex witch was limited to 3.5Gb

http://en.wikipedia.org/wiki/Address_Wi ... Extensions

SUMMARY
This article describes the 4 gigabyte (GB) random access memory (RAM) Tuning feature and the Physical Address Extension (PAE) switch.
MORE INFORMATION
The /3GB and /PAE switches in the Boot.ini file are to be used with the following products:
• Microsoft Windows 2000 Advanced Server
• Microsoft Windows 2000 Datacenter Server
• Microsoft Windows Server 2003, Enterprise Edition
• Microsoft Windows Server 2003, Datacenter Edition
• Microsoft Windows Small Business Server 2003
"Do the best, with the less" ;-)

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Post by empireum »

@atomcomputer
I am sure the option is called "/PAE".

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Post by atomcomputer »

yes, i've edited the message in the same time of your answer.
Too many windows ^^
"Do the best, with the less" ;-)

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Post by ppc_digger »

___ wrote:
empireum wrote:This is true for a 32-bit CPU system or a system running a 32-bit OS (which might well have an x64 processor). If you run an x64 OS, this limit does not apply anymore.
there is a limit, but rather large (although in a few years or something people will probably get close). weren't there some server versions of windows that could handle more (32bit not 64bit)
Current x86-64 CPUs support up to 2^40 bytes of physical RAM (1TB), and 2^64 bytes (16 HB or 16 billion GB) of virtual memory.

The reason for the 64 GB limit with PAE is that x86 CPUs (or x86-64 CPUs in 32-bit mode) use 36 bit (or up to 64 billion addresses) addressing for virtual memory, and 32-bit OSs can use the 64-bit CPU's ability to address more memory to dynamically map chunks of real memory to the 32-bit addressable space, just like they do when you have more than 4GB of virtual memory.

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Post by Frozenport »

Yet, it is important to remember that there is always x64 => Go out and get it, don't be stuck with a 32x system from the past...

Now, it would seem that what you are talking about is a revolutionary event but in reality the 4 gig limit was encountered somewhere in '99.

Anywhich way Microsoft has made a solution for anybody who actually cares to acess all that ram @ http://msdn2.microsoft.com/en-us/library/aa366527.aspx
Although it does fall short in many respects
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