Vista Ultimate 32-bit and GTX285

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Vycka

Weaksauce
Joined
Apr 28, 2008
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Here's the deal: I've got 2x2GB DDRIII RAM and a GTX285. My System Information says that I've got 3.25GB RAM. Why not only 3.00GB? Isn't it 4GB - 1GB(VRam)? Or am I missing something here?

EDIT: I tried running dxdiag and it says that I have 3326MB of RAM. What the hell's going on?
 
32 bit OSs can address a maximum of 4GB system memory. That includes GPU and system devices sometimes the memory amount doesn't make sense.
 
flak-spammer said:
32 bit OSs can address a maximum of 4GB system memory. That includes GPU and system devices sometimes the memory amount doesn't make sense.
Click to expand...

If that was the case (the video card taking up that 4 gigs of ram) then there is no way I'd have the listed 3.25GB of ram i have in my system.
 
just switch to 64 bit....i have no idea why by now computer enthusiasts don't all use 64 bit. driver problems are nonexistent in this day and age.
 
GPU's use 64-bit address space (at least in XP) on a system that supports PAE. You can have a 128mb card or a 1gb card and you will still see the same amount of RAM (3.25gb in every configuration I've seen)
 
rincewind said:
GPU's use 64-bit address space (at least in XP) on a system that supports PAE. You can have a 128mb card or a 1gb card and you will still see the same amount of RAM (3.25gb in every configuration I've seen)
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That is what I was getting at. Some people seem to think the amount of ram on the card matters when determining system ram in a 32 bit environment.
 
MurderCityDevil said:
just switch to 64 bit....i have no idea why by now computer enthusiasts don't all use 64 bit. driver problems are nonexistent in this day and age.
Click to expand...
Because codec support is still lousy for 64-bit. I have to reinstall my Vista MCE setup with 32-bit over the next few days because it randomly BSOD's while playing certain files, which work just fine in WMP. (WMP=32-bit, MCE=64-bit by default)
 
mavalpha said:
Because codec support is still lousy for 64-bit. I have to reinstall my Vista MCE setup with 32-bit over the next few days because it randomly BSOD's while playing certain files, which work just fine in WMP. (WMP=32-bit, MCE=64-bit by default)
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try CCCP works fine for me and im 64bit
 
I read about PAE(Physical Address Extension), but I didn't really get it. It says that every CPU above Intel Pentium Pro supports it. Somehow it should make a 32-bit system support up to 64GB of RAM? Maybe I'm just stupid, but could someone explain this to me in layman's terms? I mean, what's even the point in 64-bit OS if almost every CPU can make your system support up to 64GB? Surely nobody needs more than that.
 
MurderCityDevil said:
just switch to 64 bit....i have no idea why by now computer enthusiasts don't all use 64 bit. driver problems are nonexistent in this day and age.
Click to expand...


tell that to MS who all but blame the failure and bad rep of Vista on Nvidia...

I can attest my 64 bit vista - constantly gets "driver has stopped responding" with my 260gtx...and I tried every fix.
 
Vycka said:
Here's the deal: I've got 2x2GB DDRIII RAM and a GTX285. My System Information says that I've got 3.25GB RAM. Why not only 3.00GB? Isn't it 4GB - 1GB(VRam)? Or am I missing something here?

EDIT: I tried running dxdiag and it says that I have 3326MB of RAM. What the hell's going on?
Click to expand...


your not running sp1 then - vista sp1 will show 4 GB ram...the 285 does not use any system ram. Basically the 32 bit os cannot address over 4GB so you see 3.25 as "addressable" memory the rest is used for paging of some kind. PAE allowed the OS to see the extra memory but it is just seen as extra memory basically for file cacheing etc..you can use up to 16gb with the 4gt switch in conjunction with /awe but you run the risk of running out of pte's available to the kernal (OS) versus user space.

To access the extra memory applications must use the AWE api - /pae can extend the usable memory space to 3BG but an app needs to have been developed with awe to address that space.

basically 4 GB is about it ;) don't worry if you see 3.25 in your sysinfo and if you really care apply vista sp1 it will say 4gb after that :p
 
groebuck said:
your not running sp1 then - vista sp1 will show 4 GB ram...the 285 does not use any system ram. Basically the 32 bit os cannot address over 4GB so you see 3.25 as "addressable" memory the rest is used for paging of some kind. PAE allowed the OS to see the extra memory but it is just seen as extra memory basically for file cacheing etc..you can use up to 16gb with the 4gt switch in conjunction with /awe but you run the risk of running out of pte's available to the kernal (OS) versus user space.

To access the extra memory applications must use the AWE api - /pae can extend the usable memory space to 3BG but an app needs to have been developed with awe to address that space.

basically 4 GB is about it ;) don't worry if you see 3.25 in your sysinfo and if you really care apply vista sp1 it will say 4gb after that :p
Click to expand...

What are you talking about? I have SP1.
 
groebuck said:
your not running sp1 then - vista sp1 will show 4 GB ram...the 285 does not use any system ram.
Click to expand...

Yes the GTX 285 does, or more accurately anything using a PCI-E slot does.

As far SP1 goes just to clarify for a few that asked. If you had 3.2GB of available memory visible prior to installing SP1, you still have 3.2 GB available to use after you install SP1. The only thing that changed in Vista 32 SP1 was the way Vista reports the amount of memory installed. Microsoft likely changed this so they wouldn't have to take all those calls screaming where's the rest of my memory. Vista SP1 reads the total amount of memory installed in your PC rather than what's leftover after you boot into the 32-bit OS. If you wish to see the actual amount of memory available with SP1 installed, run DXDiag, and it will show you what you really have.

Where does the rest of your memory go? Usually 512MB-1GB is allocated...

The PCI memory addresses starting down from 4 GB are used for things like the BIOS, IO cards, networking, PCI hubs, bus bridges, PCI-Express, and video/graphics cards. The BIOS takes up about 512 KB starting from the very top address. Then each of the other items mentioned are allocated address ranges below the BIOS range. The largest block of addresses is allocated for todays high performance graphics cards.
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Various devices in a typical computer require memory-mapped access. This is known as memory-mapped I/O (MMIO). For the MMIO space to be available to 32-bit operating systems, the MMIO space must reside within the first 4 GB of address space.
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As far as /PAE goes, it's more trouble than it's worth from what I read, if it works at all. Here's a pretty good article from Microsoft on /PAE ...

http://support.microsoft.com/kb/929605


If anyone really wants to "use" 4GB of RAM or, they need to get a 64-bit OS as some of the others have already mentioned.
 
Vycka said:
Here's the deal: I've got 2x2GB DDRIII RAM and a GTX285. My System Information says that I've got 3.25GB RAM. Why not only 3.00GB? Isn't it 4GB - 1GB(VRam)? Or am I missing something here?

EDIT: I tried running dxdiag and it says that I have 3326MB of RAM. What the hell's going on?
Click to expand...

It doesn't work like that

It's 4GB of "address space" and some onboard/legacy devices take a chunk out of that. Then, each GPU gets 256MB mapped out for it. So if you had a quad SLI system you'd see 1 GB taken from the 4GB of address space.

Since you only have 1 GPU, you only see 256MB taken out.

Read this for more details: http://www.dansdata.com/askdan00015.htm

The only incorrect part of that article is the statement that if his card had more video memory it would take up more address space. This is not true. The cards always take up 256MB of address space no matter the onboard video memory amount. Read the bottom post here for an example:

http://forums.anandtech.com/messageview.aspx?catid=27&threadid=2259639

Not quite. Dan's article is a work-in-progress. Compare Dan's memory address allocation using GF 7800GT 256MB:

C0000000 - CFFFFFFF GeForce 7800 GT (256MB)
C0000000 - CFFFFFFF PCI Bridge (256MB)


With my memory address allocation using Radeon HD 3650 512MB:

D0000000 - DFFFFFFF Radeon HD 3650 (256MB)
D0000000 - DFFFFFFF PCI Bridge (256MB)

Twice the graphics RAM, same amount of address space. My graphics card is actually using less address space than Dan's example, when you add-up all ranges related to the graphics card (and PCI bridge).

Certain allocations must be aligned on 256MB boundaries and/or in 256MB blocks, per relevant industry specs (PCI, PCI Express, PCI Bridge, ACPI, et. al.). It is merely a coincidence in Dan's case that 256MB happens to correspond with the amount of RAM on the graphics card.
Click to expand...
 
BlueStorm said:
This is not true. The cards always take up 256MB of address space no matter the onboard video memory amount. Read the bottom post here for an example:

http://forums.anandtech.com/messageview.aspx?catid=27&threadid=2259639
Click to expand...

:p I gave-up trying to convince people of this a long time ago which is why I didn't bring it up. On my config under Vista 32 I've used cards with 128MBs, 256MBs, 512MB, and 896MB. The amount of "useable" system ram after boot was always a constant 3.5GB and did not correlate at all to the amount of RAM on the vid-card.
 
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