XP Boot Camp not useing 4gbs of ram

PapaGino

macrumors member
Original poster
Dec 11, 2015
71
5
Londonderry NH
I missed the days of XP so for a bit fun I installed XP Media Center Edition 2005 on my mid 2009 17in Macbook Pro 3.06ghz 8GB. First off I am aware that 32bit systems only can access 4gbs as a max. I always used x64 systems (even back in the day XP x64 Edition) so when it comes to x86 I'm not the best at it. The system reports only total of 2.72Gbs available. I know that in "boot camp" my 9600m GT is being used. Since at first I amused that 9400m GT was being used and it was just using some of the system memory for graphics. So what would cause XP to report only 2.72Gbs? As you can see my screen shot.
upload_2016-4-18_17-9-0.png
 

iMacDragon

macrumors 68000
Oct 18, 2008
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UK
the GPU ram has to be assigned a memory address space that the cpu can write to, which takes away from the 4gb, unlike with 64 bit OS where the gpu ram can have it's address space anywhere, and a bunch of other book keeping stuff in the BIOS that gets assigned to various ROM's. It's perfectly normal for XP to only have access to between 2.7-3.3gb of ram on a 4gb system.
 

PapaGino

macrumors member
Original poster
Dec 11, 2015
71
5
Londonderry NH
I wish they had drivers for XP X64 edition, but sadly apple doesnt provide them. Also that is strange i would think if the 9600m GT is running it wouldn't need any to reserve any ram for 9400m GT.
 

iMacDragon

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Oct 18, 2008
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I wish they had drivers for XP X64 edition, but sadly apple doesnt provide them. Also that is strange i would think if the 9600m GT is running it wouldn't need any to reserve any ram for 9400m GT.
It's not reserving ram for the 9400, the 9600's own ram has to be inside the 4gb addressible ram area for the OS to be able to use it.

Well, it might also allocate the 9400's ram and not use it for all I know too.
 

PapaGino

macrumors member
Original poster
Dec 11, 2015
71
5
Londonderry NH
Oh, But i thought the 9600GT had desecrate 512mb GDDR3 which wouldn't
It's not reserving ram for the 9400, the 9600's own ram has to be inside the 4gb addressible ram area for the OS to be able to use it.

Well, it might also allocate the 9400's ram and not use it for all I know too.
Oh, But the 9600GT has discrete 512mb of GDDR3 that it uses only for graphics. So it must just be the 9400 still allocating memory for some reason i would assume.
 

duervo

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Feb 5, 2011
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The 9600 has dedicated GDDR3. The 9400 has shared memory. If you have a 9400 in there (you won't have both that and a 9600), then it's using 256MB of system RAM, so the 2.7GB makes sense after factoring that in along with the rest.

Interesting little trip down memory lane (no pun intended), but I wouldn't go beyond that if it were me. Get that mess off your system, if it were me. Keep it to the 32bit limits (the trip down memory lane, I mean ... ok that one was on purpose), and get rid of it. I'm calling it a "mess" because it hasn't been receiving any security updates for years at this point. So, it's like a corpse that's been rotting in the sun for ages by now.
 

duervo

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Feb 5, 2011
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If that's the case, then that's even more data to support the numbers that you are seeing.

That's how much memory you have left for your programs when running that crap.

Haha