32-bit and 4gb memory limitation????

[WR]

PAE is Physical Address Extension. It is a CPU feature that an OS can choose to use or ignore (for compatibility reasons). It's only arbitrary that the extension is only 4 bits; Intel designed it that way.

What you mean is almost every 32-bit x86 chip since the Pentium Pro has a special 36-bit addressing mode.

A 32-bit OS on a CPU without PAE wouldn't be able to address past 4 GB. It's not in the nature of a 32-bit OS to address past 4 GB of main memory. Doing so requires hardware and device driver support.

Probably two. After all the two cores won't show the same.. One renders the upper part, one the lower.

See, I don't like guessing on this because there is an even stronger argument. The 1 GB framebuffers for each 4870 are mirrored and then each core can read its own copy to render its top or bottom half, or every other frame, or however the user sets the rendering mode. Since you have 1 GB effective VRAM, the OS should have no reason to be addressing 2 GB, right?

 

[sighQ2]

Does this interesting ram functionality only apply to Vista? This approach is news to me although I have been stumbling over bits of it here and there for a while now.

The above system B looks pretty normal; but the Vista version is like pretty foreign.

I have been out of the loop for a few years and I have been researching hardware for a while, planning new system - and that will be AMD btw cos I can't support antitrust monopoly etc. AND I certainly would tend to discourage anyone who is not tekky inclined from investing in nejalem for the purpose of e-penis elongation or other ego related fantasy cos it's too new too expensive and you are headed for tekno hell or at least a very interesting time requiring a lot of patience and learning the hard way.

But this is not about hardware and I think it's a Vista thing. Kinda like microsoft takes us closer again to server tek, as they did with XP. At that time M$ intro'd new ACPI and caused a lot of obsolete hardware. It was published pre xp release, and so the hardware mftrs were warned and had to comply.

So IF THIS IS VISTA, has microslop published KB's about this?
Is vista using virtual mem differently?
Am I in the ballpark????????
Does anyone really know?

I am intending to go 64-bit OS - esp. with AMD cos AMD has been selling 64-bit processors for almost a decade. spintel is pretty new at it, and I think i7 is spintel first REAL 64 - the previous have either failed or been software instituted - fake. (amazing how nejalem near copies AMD's architecture)

The only info I had, before this posting by "notherdude", has indicated that 32bit OS will only show you 3.2 of 4 gigs - and I adopted that info, have shared that info, and decided to go 64-bit OS to avoid ram limits and wastage. But this is a whole different approach.

Another thing - I tend to study windoze and disable cleanly and safely a lot of useless features, as I am sure many others also do.
One tactic was to set virtual mem to NONE and then del the pagefile.sys. I wonder how Vista would respond to that treatment. The idea was, in gaming, to promote the use of fast ram rather than the use of comparitively slow hdd-access-speed virtual mem, not to mention the thrashing that occurs on the hdd with usage of v-mem. Idiot vista apparently loves virtual mem.

But I am still on xp and have basically no experience w wishta.

If anyone can further elaborate on what has been mentioned here, or link me to some crazy tek info or a kb or other site, that would be appreciated. Is there a name for all this that could be used to google? Any info thxx/

Thank you to notherdude for sharing.

sigh
.

EDIT = I just read the "Dan's" link - a very good read. I did not realize that the old dos 8086 era stuff was still in play in that manner. And the mem limits are well explained.
i still have a lot of questions about vista and esp. what happens if you kill the VM.

That brought back a lot of memories of things like
ECHO OFF
LH C:\DOS\EMM386.EXE /NOEMS
and trying to preserve that max 640K cos it determined the max program size you could run. Like DOOM.

A major issue in those days - no matter what kinda mess your pooter was in =
"Never mind you can't open Word 3, and you lost your resume cos it crashed before you saved it - Will DOOM still run?"
= Nothing like having your priorities straight. Things haven't changed much at all.

I remember having an IBM PS2 286 w 1 meg ram - you could HEAR every clock tick!

 

[MarkG]

It's not in the nature of a 32-bit OS to address past 4 GB of main memory.

So are you claiming that Linux is 'unnatural'?

Microsoft have PAE support for Windows, because it's available in some of the server versions; they just deliberately cripple the 32-bit desktop versions to limit them to 4GB of physical memory. It's a hack, but it's better than not using >4GB of memory at all.

 

[Kkkk1]

I'm assuming that is 1.2GB just idling (with nothing open). Many games an really gobble down ram (besides Crysis). My current Vista 32 is tweaked down so it only uses 400MB or less with nothing open, yet it can still start running low on ram (I have 2 GB). That's why I'm going to Vista 64 and 4GB in my next build. I think 64 is fairly stable now. Do you have both versions (32 and 64)?

1.2 gig is when I've loaded XP pro and running Crysis in medium settings half way through a level!! So was assuming 3Gb under Vista would be fine. Judging by all the posts it appears i'm wrong and most people are saying get 6Gb.

 

[sighQ2]

You need to educate yourself re the path your ego is taking you down. Listen and learn. Do research. Read all you can. Slowly. And not in forums. You are confusing yourself. Back to basics first. Otherwise you just keep stumbling around chasing other people's opinions. Buy a broken pc and take it all apart and then make it work - with only your own research.

- any thrift store -
cost = $5
what you might learn = priceless!
Then donate it to the thrift store

Then do it with your old pc.
Then a friends pc.
Don't quit till they all are perfect.

Then build your own basic functional unit. Then add to it.
(what's a basic functional unit?)

Either that or buy a dell. better to buy a busted dell.

Good luck.

 

[Kkkk1]

Sod this, i'm going for the following:-
Vista 64
6Gb DDR3 tri channel
X58 mobo
i7 920
GTX 260 216core
Corsair 1000W PSU, as i'll SLi later
22In TFT

Job done. Thanks for all the advise.

 

[GenRabit]

Actually, a 32-bit x86 OS can address 64GB of memory, but 32-bit desktop Windows versions won't.

The 4GB limit is per-application, but the CPU can handle 64GB of physical memory; Microsoft only allow that on server versions of Windows. 32-bit PAE Linux kernels, for example, can manage 64GB of RAM.

Windows XP and Vista has a 2GB limit per application under 32bit. Passing that limit and application is about to crash.


And 32bit os can only handle 4GB. The PAE extension use is an ugly path to walk down. The way I understand it, is that with an OS using the PAE, your still only have access to 4GB, but you can swap between "4GB" blocks..

To me this sounds like a nightmare, and I'd say go 64bit.

 

[notherdude]

So are you claiming that Linux is 'unnatural'?

Microsoft have PAE support for Windows, because it's available in some of the server versions; they just deliberately cripple the 32-bit desktop versions to limit them to 4GB of physical memory. It's a hack, but it's better than not using >4GB of memory at all.

The story goes that at one time you could enable PAE to make more RAM available in XP but it caused too many problems, possibly because of poorly written drivers IIRC, this may or may not be the case but unless you can offer more proof I think it is a bit unfair to say that MS made this limit arbitrarily. A server OS is not likely to run the same vast range hardware of all makes and quality variables as a consumer version like XP, which may account for the difference there. It should be noted that a 64 bit OS costs no more than a 32 bit OS so at this point it is hard to see how this limitation could possibly profit MS much. Maybe before XP 64 was available, if your only choice was Server or XP, then yea, maybe. Maybe being the key term.

Mark Russinovich (author of process explorer and a MS tech fellow and brain) has something interesting to say on his blog on this subject:

However, by the time Windows XP SP2 was under development, client systems with more than 4GB were foreseeable, so the Windows team started broadly testing Windows XP on systems with more than 4GB of memory. Windows XP SP2 also enabled Physical Address Extensions (PAE) support by default on hardware that implements no-execute memory because its required for Data Execution Prevention (DEP), but that also enables support for more than 4GB of memory.

What they found was that many of the systems would crash, hang, or become unbootable because some device drivers, commonly those for video and audio devices that are found typically on clients but not servers, were not programmed to expect physical addresses larger than 4GB. As a result, the drivers truncated such addresses, resulting in memory corruptions and corruption side effects. Server systems commonly have more generic devices and with simpler and more stable drivers, and therefore hadn't generally surfaced these problems. The problematic client driver ecosystem lead to the decision for client SKUs to ignore physical memory that resides above 4GB, even though they can theoretically address it.

The consumption of memory addresses below 4GB can be drastic on high-end gaming systems with large video cards. For example, I purchased one from a boutique gaming rig company that came with 4GB of RAM and two 1GB video cards. I hadn't specified the OS version and assumed that they'd put 64-bit Vista on it, but it came with the 32-bit version and as a result only 2.2GB of the memory was accessible by Windows.

From here: http://blogs.technet.com/markrussinovich/

also from Mark:

Because device vendors now have to submit both 32-bit and 64-bit drivers to Microsoft's Windows Hardware Quality Laboratories (WHQL) to obtain a driver signing certificate, the majority of device drivers today can probably handle physical addresses above the 4GB line. However, 32-bit Windows will continue to ignore memory above it because there is still some difficult to measure risk, and OEMs are (or at least should be) moving to 64-bit Windows where it's not an issue.

 

[notherdude]

Sod this, i'm going for the following:-
Vista 64
6Gb DDR3 tri channel
X58 mobo
i7 920
GTX 260 216core
Corsair 1000W PSU, as i'll SLi later
22In TFT

Job done. Thanks for all the advise.

You have chosen well for the future my son.