Re: OT: Recommend new high end PC?

On Wed, 06 Feb 2008 16:20:33 +0000, Gareth Robert Halfacree
<usenet@xxxxxxxxxxxxxxx> wrote:

Mark wrote:
On Wed, 06 Feb 2008 11:38:29 GMT, Daniel James
<wastebasket@xxxxxxxxxxxxxxxx> wrote:
If you put in a couple of 768MB graphics cards you'll have less than
2.5GB of addressing left over for RAM.

I thought only integrated graphics cards steal space from the main
system memory?

It's not stealing RAM, but address space. 32-bit computers (PAE
excepting) can have up to 4GB of /address space/. The first chunk is
used for addressing RAM. Graphics card memory needs addressing too, so
that comes out of the remainder.

I wonder why graphics cards need much address space from the CPU?
Doesn't the PCI/AGP bus have alternative ways of transferring data
than mapping main memory space? I haven't kept up with the latest
technology here, but I'm sure it used to work this way.

There certainly used to be something called an "AGP aperture" which I
thought was for this purpose.

M.
.

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