How does memory addressing with integrated video cards work

[AncientPC]

If I am running a 32b OS I have 4GB of address space available. Assuming 3GB of system RAM and a 1GB discrete video card RAM I am using 100% of available address space.

If I have 4GB system RAM and an integrated video card, how much of the address space is used by the video card? Does it fluctuate? How can I tell within XP / Vista / Ubuntu how much memory the integrated card is using?

Also, assuming an integrated video card and a FSB the latency between video and RAM is another contributing factor to lower integrated video card performance vs discrete, right?

 

[ViRGE]

You'll have anywhere between 3.3GB and 3.7GB available, depending on what other devices are present in the system. AFAIK there's no easy way to tell quite how much address space a single device is using.

 

[Nothinman]

how much of the address space is used by the video card

That depends on the video card.

Does it fluctuate? How can I tell within XP / Vista / Ubuntu how much memory the integrated card is using?

It varies per-card but it doesn't fluctuate at runtime.

 

[Steve]

Originally posted by: ViRGE
You'll have anywhere between 3.3GB and 3.7GB available, depending on what other devices are present in the system.

How do you know? Is this just a random range of numbers you're pulling out?

AFAIK there's no easy way to tell quite how much address space a single device is using.

Text - does this help?

 

[Nothinman]

How do you know? Is this just a random range of numbers you're pulling out?

Pretty much, but it's where most people end up falling so it's a good initial guess.

 

[Steve]

Yeah, I didn't mean to lash out, I just get disgusted when some people throw numbers around and make it sound definite. I know ViRGE wasn't intending that.