Some RAM not usable on WIndows 7 Bootcamp? Why?

[iSayuSay]

Okay so I've just got my iMac .. it's hi end 27" + i7 + 6970M 2GB

Now I've done installing Windows Bootcamp Win7 32 bit) .... now I've just installed Sims3 for testing

Wow .. game looks smooth even on 1440p .. but sometimes there's a bit stutter. NOW I don't like that!! NOt on Sims 3, and not on a $2300 computer .. So I look into Task Manager and there it was...

It said my usable RAM is around 2.2GB while I have 4GB standard RAM installed. And I only have 5% of free RAM while Sims 3 was running.

Now I understand that Windows 7 32 bit has limitation for RAM, but certainly not 2.2GB, right ?!! It should be around 3.7GB or something.

Now I have 4GB of RAM, running via Bootcamp. Why Windows can't use the remaining RAM? .. it said there is around 1.7GB reserved for hardware. What hardware? 6970M has its own RAM, not shared or something, right?

What have I done wrong? Does add some more RAM would help? I don't have 64bit copy of Windows7, so please help me how to get more usable RAM with 32 bit WIn7 on bootcamp?

 

[Ace134blue]

Nothing you can do with 32bit. Maximum Ram for 32bit is 4gb subracted by video memory. So you have Less then 3GB of ram usable. 2.2GB is about right.

 

[iSayuSay]

Nothing you can do with 32bit. Maximum Ram for 32bit is 4gb subracted by video memory. So you have Less then 3GB of ram usable. 2.2GB is about right.

Hmm okay .. but why? 6970M has its own VRAM, right? It wasn't shared with system RAM or something. Why there is this RAM taxing because GPU has more VRAM? Or 4GB is TOTAL usable RAM on 32bit? (sorry .. but I really never heard that)

How about 27" base model. GPU has 512MB VRAM, and standard RAM around 4GB. Therefore in Win7 32 bit, we can get around 3.5GB?

So .. higher VRAM actually much worse for 32bit Bootcamp?? I thought the limitation only for system RAM? Not including GPU ...

 

[Toddi]

It depends... In the most cases your GPU Ram is included to the 32Bit Memory limitation of 4 GB adressable Ram.

http://msdn.microsoft.com/en-us/lib..._cards_and_other_devices_affect_memory_limits