graphics memory and 32 bit Vista

[frozentundra123456]

I was just wondering what would happen if I used a 1GB memory graphics card with a comp that has 3GB of ram and 32 bit Vista. This would give 4 GB of total ram. I understand that 32 bit vista cannot use more than about 3.5 GB of ram, so how would the computer allocate the ram between system ram and graphics ram?
Would I actually lose performance in non-graphics applications because the comp could not use the full 3GB of system ram?

 

[geoffry]

Video ram on a GPU is not used by Windows as if it were normal system ram, it is only used for graphics.

 

[Martimus]

However under Vista this results in the application and the WDDM effectively playing a game of chicken: both are consuming virtual address space out of the same 2GB pool and neither is aware of the other doing the exact same thing. Amusingly, given a big enough card (such as a 1GB Radeon X2900XT), it's theoretically possible to consume all 2GB of virtual address space under Vista with just the WDDM and the application each trying to manage the video memory, which would leave no further virtual address space for anything else the application needs to do.

http://www.anandtech.com/gadgets/showdoc.aspx?i=3034

http://www.anandtech.com/cpuch...ts/showdoc.aspx?i=3044

http://www.anandtech.com/printarticle.aspx?i=3060

(above is the 3 part article about windows 32-bit addresing space issues.)


KB940105 Hotfix should fix some of the addressing issues though. It should be included in Vista SP1, so you probably are already covered by it.

 

[Rifter]

I think what he is trying to say is if he uses a 1GB vid card will it reduce the amount of ram windows can address for running itself and all applications, i think the answer is yes. You should upgrade to a 64bit OS, if you own vista already you can get MS to send you a 64bit DVD for $13 thats what i did. I bought Vista home basic Retail which only comes with 32bit DVD and i ordered a 64bit DVD from MS for the cost of shipping. The problem is 32bit OS can only address 4GB total memory including everything your computer uses memory for such as sound card, NIC, video card, any kind of HD/DVD cache and system memory. I Am currently running 32bit Linux on the rig in my sig and with 256MB allocated to my video card and 4GB of system memory installed linux will address only 3.2GB of ram. You would think it would see 3.75GB but there is more than your video card and system memory that the OS needs to address. 64bit is the way to go.

 

[aka1nas]

Originally posted by: geoffry
Video ram on a GPU is not used by Windows as if it were normal system ram, it is only used for graphics.

Video RAM is addressable in Windows and comes off your total virtual addressing space.

 

[geoffry]

Woops, I misunderstood his question.

Disregard my first post, these guys are right.

 

[zagood]

Link to the hotfix - worth a read (in addition to the AT articles mentioned earlier) to see what's going on:

http://support.microsoft.com/kb/940105

 

[frozentundra123456]

Thanks for all the replys. I have been using a 512mb card without problem with 3gb of ram and 32bit Vista. I will stick with a 512mb card. I only use lower resolutions so 1gb of video memory is probably not needed anyway. However, this makes it unfortunate that so many graphics card makers make 1GB lower performance cards which cannot use that much memory.

 

[geoffry]

Originally posted by: frozentundra123456
Thanks for all the replys. I have been using a 512mb card without problem with 3gb of ram and 32bit Vista. I will stick with a 512mb card. I only use lower resolutions so 1gb of video memory is probably not needed anyway. However, this makes it unfortunate that so many graphics card makers make 1GB lower performance cards which cannot use that much memory.

Ya, that is definitely annoying.

But the general public sees the high ram number and think its stronger than Mike Tyson.