Mac Pro + Vista Business = only 2GB of RAM???

[ckurowic]

to see more than 2GB of RAM in Windows, you will need a 64bit version of Vista or XP installed. 32bit XP (regular XP) and 32bit Vista will only show 2GB of ram.

What TBi is saying is correct, and no amount of switches if configuration will change this. Its to do with the way Apple's EFI implements the legacy BIOS. 64bit OSes will see all your RAM, 32bit Windows will only ever see 2GB.

Trust me on this, I have installed various Windows in BC loads of times, and the only way to get more than 2GB show up is to use a 64bit windows.

XP on my machine sees 3GB of my 4GB, not 2GB. It seems to be irregular in what it chooses to see...

 

[MacsRgr8]

XP on my machine sees 3GB of my 4GB, not 2GB. It seems to be irregular in what it chooses to see...

I think the memory controller is also part of the blame.

I have a Mac Pro '08 with 4 GB RAM. (I now have 8 GB, but that is after the following experiments...)

I have some default installations, and here is which Windows can "see" how much RAM:

- Windows XP Pro 32 bits SP 2 and SP 3: 2 GB RAM
- Windows Vista 32 bits: 2 GB RAM
- Windows Vista 32 bits SP 1: 4 GB RAM
- Windows Vista 64 bits, and 64 bits SP 1: 4 GB RAM

(I now have 8 GB RAM, and Windows Vista 64 bits SP 1 sees all 8 GB)

 

[Stridder44]

I think the memory controller is also part of the blame.

I have a Mac Pro '08 with 4 GB RAM. (I now have 8 GB, but that is after the following experiments...)

I have some default installations, and here is which Windows can "see" how much RAM:

- Windows XP Pro 32 bits SP 2 and SP 3: 2 GB RAM
- Windows Vista 32 bits: 2 GB RAM
- Windows Vista 32 bits SP 1: 4 GB RAM
- Windows Vista 64 bits, and 64 bits SP 1: 4 GB RAM

(I now have 8 GB RAM, and Windows Vista 64 bits SP 1 sees all 8 GB)

In actuallity though, Vista 64 can use up to 128 GB of RAM.

 

[Infrared]

- Windows Vista 32 bits: 2 GB RAM
- Windows Vista 32 bits SP 1: 4 GB RAM

Gotta be careful here:

http://support.microsoft.com/kb/946003

"This change in Windows Vista SP1 is a reporting change only."

 

[ayeying]

Has anyone considered its a problem with the EFI simulating BIOS for Windows to run?

 

[MacsRgr8]

Gotta be careful here:

http://support.microsoft.com/kb/946003

"This change in Windows Vista SP1 is a reporting change only."

Hmm.... I see.

Luckily, I am not running Vista 32 bits anymore, just 64 bits.