On Tue, 11 Oct 2005, David Becker wrote:
Steffen Kluge wrote:
On Tue, 2005-10-11 at 09:32 +0200, David Becker wrote:
Sorry if I sound like I'm whining over this, but the market has become
so untransparent because of these architectures.
No worries, this is very interesting.
Btw, "lcpci -v" reports 128MB of memory for the X300, I assume 64MB
on-board + 64MB extra?
Strangely, the "stolen" 64MB aren't missing in the output of "free" (as
is the case with shared video memory adapters).
It could be that 128MB reflects the graphics card's addressable memory
while the extra 64MB is not actually in use.
You'd have to run something that uses more than 64MB VRAM and then check
the available system memory. It's not unlikely that the hypermemory is
reflected differently than shared memory.
radeon x300 mobile parts are available in 3 flavors...
32mb, 64mb, discrete... while the discrete part could potetially have no
memory attached, it would be more common for it to have some attached.
dell for example sells the inspiron 6000 with x300's that have either
no memory (64MB hypermemory they call it) or 128MB. desktop x300's with
256MB of ram do exist, though why you would get one is another question
entirely.
Hypotheses:
Graphics card has 64MB on board memory
Graphics card can address 128MB VRAM
Hypermemory architecture allocates system memory for vram on demand
Shared memory architectures allocates system memory for vram on power up
So given these hypotheses, a plain-vanilla shared memory architecture
immediately reserves system memory vram, while the hypermemory (shared
memory) architecture only uses/reserves the augmented memory when it's
out of on board vram?
It get's more confusing since a cousin of mine recently purchased a
laptop based on ATI's 200M chipset. I haven't run linux on it, but
Windows reports 512MB-128MB system memory. And the graphics card uses
128MB shared memory. Given that this card follows the hypermemory
architecture and my hypothesis on how hypermemory is allocated/reserved,
windows should report the system memory as more than 512-128. Either
Windows reports this differently than linux, or the ATI 200M chipset
immediately (on power up) reserves system memory for VRAM because this
particular card doesn't have *any* on board memory. Or my hypothesis on
the difference in behaviour between HyperMemory and Shared Memory
architectures with respect to system memory reservation is wrong.
If these laptops were mine, I'd open them up and look at the graphics card.
Things are getting hairy.
regards,
David
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