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32bit Windows with octo core. Does the 2gb memory limit really slow it down

nihilisticmonk

nihilisticmonk

macrumors 6502
Original poster
May 4, 2005
297
38
Hi Guys,

Just put my order in to replace my 2007 macpro with a 2008 revision.

As we all know, the 32 bit versions of windows only detect 2gb of memory.

With my 4 core, it runs games pretty well, the only drawback is the ATI 1900XT.

Since with an 8 core, it's only going to see 256mb per core in xp does this slow down windows horribly for gaming tasks?

Am I going to have to shell out for 64bit vista to make the most of crysis etc?

And then, are the bootcamp drivers not going to work in 64bit windows:eek:
 
I have 64-bit Vista running in Boot Camp and the drivers supplied with Early 2K8 Mac Pro are fine. I would highly suggest running 64-bit if you plan on playing hi-end games, but the bottom line is, it's down to you. If you feel it lagging, and unresponsive, or you KNOW you are going to be using powerful apps just go straight for 64-bit.

Also, I'm not sure, but I think 32-bit windows should show close to 3.2~GB RAM.
 
just go with 64bit Vista.

Another complication is that you need a 64bit version of either Vista Business or vista Ultimate to see both physical processors.

64bit versions of vista home will only see the first 4 core processor and totally ignore the other one.

hope this helps

Colin.
 
You should see upwards of 3.5GB with a 32-bit Windows OS. We use eight-core HP workstations with Windows XP / Windows Vista Enterprise 32-bit and 4GB and our machines see 3.5GB plus all eight cores.

Also, Windows does not assign a specific amount of RAM to each core. So all eight cores will be able to address the entire available RAM amount.

And finally, the latest Mac Pro Boot Camp driver CD does support 64-bit versions of Windows XP and Vista.
 
CWallace said:
You should see upwards of 3.5GB with a 32-bit Windows OS. We use eight-core HP workstations with Windows XP / Windows Vista Enterprise 32-bit and 4GB and our machines see 3.5GB plus all eight cores.

Also, Windows does not assign a specific amount of RAM to each core. So all eight cores will be able to address the entire available RAM amount.

And finally, the latest Mac Pro Boot Camp driver CD does support 64-bit versions of Windows XP and Vista.
Click to expand...

is it really both xp an vista?
if true
who wants vista then?
 
CWallace said:
You should see upwards of 3.5GB with a 32-bit Windows OS. We use eight-core HP workstations with Windows XP / Windows Vista Enterprise 32-bit and 4GB and our machines see 3.5GB plus all eight cores.

Also, Windows does not assign a specific amount of RAM to each core. So all eight cores will be able to address the entire available RAM amount.

And finally, the latest Mac Pro Boot Camp driver CD does support 64-bit versions of Windows XP and Vista.
Click to expand...

I see. My old Macpro had 4gb, but only ever detected 2gb in xp.


I didn't know they'd bundled 64-bit drivers with the new mac-pro's (Wasn't the case with the 2007's).
That's made the decision for me right there, OEM Vista Ultimate 64 Bit for the win!

Cheers!
 
Akula971 said:
I've windows XP Pro on a boot camp drive, and all it ever sees is 2GB, should it see more? and if yes, then why does it not?
Click to expand...

my understanding is (correct me if i'm wrong here) that any one app in a 32 bit os can only use 2 gig, but the os should see/use up to 4.

so again, has anybody got their MP to see more than 2 (under xp)?
 
You can only see somewhere between 2.75 and 3.25 GB's of RAM with a 32 bit OS. The Mac Pro has an issue where it won't see more than 2GB.

Contrary to what people are saying, the only time you really want 64 bit is when you're using massive amounts of data, i.e. final cut or something of that nature. XP runs perfectly well with a 500Mhz processor and 64MB of RAM, so just get XP 32. 64 bit OS's use more space (each piece of data is 64 bits long instead of 32), so unless you have lots of RAM, 64 bit is pointless.
 
On Buying Vista

colincarter said:
64bit versions of vista home will only see the first 4 core processor and totally ignore the other one.

Colin.
Click to expand...

Is this true for the Premium version of Home Vista as well? The other versions are more expensive, so that sounds like a M$ trap.
 
XP and Vista home editions only support a single physical CPU. The Vista home editions are also RAM limited to 8GB and 16GB for the Basic and Premium x64 editions respectively.
 
steveza said:
XP and Vista home editions only support a single physical CPU. The Vista home editions are also RAM limited to 8GB and 16GB for the Basic and Premium x64 editions respectively.
Click to expand...

but xp pro must support more, when i open activity monitor under xp pro it shows all 8 cores....
 
The early 2008 Mac Pro will only see 2GB of RAM under XP Pro 32-bit, but will see both CPU sockets (so all 8 cores are available). This is because of EFI, but is a common problem. The big limitation of 32-bit operating systems is that every piece of memory must have an address below the 4GB mark. This means that video cards (which have a LOT of RAM these days) must use some of that address range, RAID controllers, network cards, the lot.

In the "old" days, this might only account for a couple of hundred meg of RAM. No biggie, really. Then video cards started shipping with 512MB RAM on them. Or worse.

I can't account for why a full 2GB is allocated on a Mac Pro, but I'd assume it is to do with the seriously high-end peripherals Apple expects you to use. RAID controllers with 512MB RAM on them, dual 512MB video cards, etc.

This isn't just a Windows issue either. This is all because of the way modern PCs are designed overall - direct memory access is a pain in the rear here.

64-bit OSs have the same issue BTW. They allocate a nice big chunk of memory to hardware - fortunately for us though, this area of memory is so far up in the sky that we haven't noticed it yet. We're not likely to either, but I'm sure somebody once said that about the 4GB issue.

Vista 32-bit will probably report all 4GB of RAM as being installed, but unless it does something unbelievably tricky with memory addressing I doubt you'll have access to all of it.

Vista 64-bit will see all your RAM, but app compatability issues will haunt you for life.

XP 64-bit will also see all your RAM, but Apple won't give you drivers for it so expect a long night of trying to make the thing work.

XP 32-bit won't see more than 2GB but it'll work fine for most things.

Personally, I have 10 GB RAM on my Mac Pro. I run XP Pro 32-bit for gaming. Yes, the RAM shortage annoys me but it has had zero impact on my actual gaming experience so far. I'll try Vista 64-bit again soon, but to be honest I expect Vista will be worse than XP regardless of how much RAM I can throw at it.
 
CWallace said:
Correct. XP Pro and Vista Ultimate, Enterprise and Business all support all the cores in each of up to two (?) CPUs (so two times four cores).
Click to expand...

Yeah, the license doesnt work by cores, etc.

It works by sockets on the mainboard.

For instance, XP Home Edition will work fine with a Quad Core processor, because it is one socket.

XP Home Edition will not work with a Dual Processor system, as its 2 sockets, each fitted with a single core processor.
 
I've been running Vista 32bit SP1 for awhile now. The only reason I boot into windows is for gaming. Sure it kinda bugs me that Windows will only use 2 of my 6gb of ram but its not a huge issue. 64bit Windows still scares me. Seems like its more headaches than what its worth.
 
ReallyRedCobra said:
I've been running Vista 32bit SP1 for awhile now. The only reason I boot into windows is for gaming. Sure it kinda bugs me that Windows will only use 2 of my 6gb of ram but its not a huge issue. 64bit Windows still scares me. Seems like its more headaches than what its worth.
Click to expand...

I've been running 64-bit vista for just under a year now on different machines, don't be afraid! It really doesn't cause many (if any) problems. Running smoother on my Mac Pro than any other machine too.
 
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