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wcalderini
Aug 20, 2007, 09:19 AM
The basics.
New SR AL iMac 20 inch ($1499 Model).
Installed 2x2GB Ram chips. All looks fine in OSX, 4GB recognized.
Bootcamp 1.4, Fresh Windows XP Pro installed, under "system" control panel tab it is only showing "2.98 GB" memory installed.
I could understand it if only 2GB appeared as it may not be seeing one of the chips, but 2.98? That does not make a whole lot of sense.
Just wondering if there was some "Windows" memory limit on this chipset under XP that I had not read about.
Would upgrading to Vista make a difference?
Have I done something noobish and not realized it?
Any similar experiences out there?

BC



rainydays
Aug 20, 2007, 09:21 AM
XP cannot use more than 3GB. Upgrading to Vista will do it for you.

wcalderini
Aug 20, 2007, 09:30 AM
That will do it then.
Thanks a bunch.
Never knew that.
And was actually looking for a good enough excuse to plunk down the $99 for the upgrade anyway.

BC

TBi
Aug 20, 2007, 09:40 AM
XP cannot use more than 3GB. Upgrading to Vista will do it for you.

At least post accurate information...

Vista 32-bit has the same limitation as XP 32-bit.

However, BOTH XP 64-bit and Vista 64-bit can see more than 3 GB.

So vista won't solve your problem unless you get the 64bit version.

EDIT: This is a limit of the 32-bit memory address space. You don't have this problem in OSX because it's running in 64bit.

wakerider017
Aug 20, 2007, 10:28 AM
At least post accurate information...

Vista 32-bit has the same limitation as XP 32-bit.

However, BOTH XP 64-bit and Vista 64-bit can see more than 3 GB.

So vista won't solve your problem unless you get the 64bit version.

EDIT: This is a limit of the 32-bit memory address space. You don't have this problem in OSX because it's running in 64bit.

Woah, I thought Tiger was 32bit...


They are making a big deal out of leopard being 64bit.


"Leopard delivers 64-bit power in one, universal OS. Now the Cocoa application frameworks, as well as graphics, scripting, and the UNIX foundations of the Mac, are all 64-bit. And since you get full performance and compatibility for your 32-bit applications and drivers, you donít need to update everything on your system just to run a single 64-bit application."

aLoC
Aug 20, 2007, 10:37 AM
Tiger is partially 64-bit. It can use more than 4GB memory and command line apps can be 64-bit but not GUI apps. In Leopard everything is 64-bit even gui apps.

TBi
Aug 20, 2007, 10:43 AM
Exactly as Aloc said.

Also read this (http://developer.apple.com/macosx/64bit.html) and this (http://developer.apple.com/macosx/tigerdevintro.html)

rainydays
Aug 20, 2007, 10:53 AM
At least post accurate information...

Vista 32-bit has the same limitation as XP 32-bit.


Oh yeah, you are right. Sorry about that.

wakerider017
Aug 20, 2007, 01:16 PM
Exactly as Aloc said.

Also read this (http://developer.apple.com/macosx/64bit.html) and this (http://developer.apple.com/macosx/tigerdevintro.html)

Okay thanks, didn't know that. :)

colorspace
Aug 20, 2007, 01:22 PM
That all makes sense - but why can GUI apps like PS access more than 3GB in Tiger?

whateverandever
Aug 20, 2007, 03:51 PM
That all makes sense - but why can GUI apps like PS access more than 3GB in Tiger?

Because darwin supports it.

Leopard being 64-bit across the board means that GUI apps will be compiled to take advantage of 64-bit math. "64-bit" isn't some kind of magic that lets you use lots of RAM :]

Most apps won't run noticeably different compiled for 64-bit CPUs, and some will actually run slightly slower depending on the compiler (32-bit calculations are faster, of course, and if your compiler decides to use a 64-bit operation when it wasn't needed...)

TBi
Aug 20, 2007, 06:09 PM
Most apps won't run noticeably different compiled for 64-bit CPUs, and some will actually run slightly slower depending on the compiler (32-bit calculations are faster, of course, and if your compiler decides to use a 64-bit operation when it wasn't needed...)

Intel chips will run faster in 64-bit mode due to increased register count. G5 chips will be the same or slower.