Quick 32 bit OS memory question

[Scottyyy]

Right, I know 32 bit OS' can only support 4GB of total system memory. Right now i'm running 4GB of RAM and a 1GB HD4850 on XP 32 bit. I know, I'm not getting full use of my RAM but I messed up my Win7 64bit install and haven't gotten around to reinstalling it yet. Basically my question is, since Windows tells me I'm using 3.5GB of RAM, am I only using 512MB of my HD4850 RAM? Or is Windows reporting it wrong, and I'm using 3GB of RAM and the full 1GB of VRAM?

Cheers

[spac3d]

Graphic card ram has nothing to do with it mate, just your system memory. You can only use 2^32, which is 3-3.5GB of system memory yes, 1GB is probably going to waste.

[alsenior]

the ram on you graphics card (and the sram on just about every other device on you machine) is subtracted from the 4GB limit. while windows says it can address 3.5GB in reality ot can only address about 2.75 GB

[dangel]

The limit isn't memory - it's 32bits worth of addressing which has to be shared with every system device - memory included. This has been covered ad infinitum on here

[Scottyyy]

The limit isn't memory - it's 32bits worth of addressing which has to be shared with every system device - memory included. This has been covered ad infinitum on here

Sorry, having a bit of a slow day. Can you put that into context for my situation, with the 4GB of RAM and 1GB of VRAM? How much is being used and all that.

Cheers

[spac3d]

In simple terms, the way a 32-bit Windows OS is programmed, it cannot physically use the more than 2^32 address spaces, which works out in the real world as 2.75 GB of ram being physically used. So if you have more RAM, windows 32-bit cannot utilise it.

64-bit OS is 2^64, so alot more address space.

Your graphics card ram isn't part of this, it's completely seperate.

[Fraz]

In simple terms, the way a 32-bit Windows OS is programmed, it cannot physically use the more than 2^32 address spaces, which works out in the real world as 2.75 GB of ram being physically used. So if you have more RAM, windows 32-bit cannot utilise it.

Your graphics card ram isn't part of this, it's completely seperate.

Hmm, you're saying one thing and then contradicting yourself. But basically, what you are saying regarding video RAM is incorrect.

A 32-bit OS can access 32 bits of address space, as you say. 2^32 is 4294967296, or 4 GB exactly (well, 4 GiB technically). The graphics card RAM is indeed part of this, as it has to be addressable. Every single piece of addressable hardware gets subtracted from the 32 bit wide address space, with whatever is left over as being available for system memory.

So, to me it sounds like your OS is lying to you, or you only have a 512 MB graphics card. If it truly is a 1GB graphics card, you should have some small amount less than 3GB of system memory once you've subtracted other things that take up address space (such as sound cards, etc).