A few questions about integrated graphics

Roland Scheidegger sroland at tungstengraphics.com
Tue Aug 19 17:36:22 PDT 2008

On 19.08.2008 20:41, Chris Pemberton wrote:
> My last question can best be asked using a specific example:
> An Intel DG33TL motherboard has a GMA 3100 graphics processor built in.  
> It can accept CPUs with a 1333 or 1066 or 800 MHz system bus, and either 
> 667 or 800 MHz RAM.  Obviously if any graphics processing is offloaded 
> to the CPU, clock speed, bus speed and ram speed are crucial.  But for 
> graphic processing handled solely by the integrated GPU, will the bus 
> speed or ram speed have any effect?  Or does the GPU communicate with 
> the shared RAM at a "fixed" speed beyond the control of the system 
> builder?   Did that make sense?  Will choosing the faster system bus or 
> ram speed allow the integrated GPU to read/write to shared memory more 
> efficiently?

Typically faster ram will help since the memory bandwidth the gpu can
use goes up (since the memory controller is in the chipset). Bus speed
OTOH shouldn't really have much of an effect, though of course the
cpu->gpu communication will be faster (I'm just suspecting it won't make
much of a difference, but I don't have any numbers to back this up).
Note that this is quite different to AMD chipsets - especially the HD
3200 IGP is known to be significantly faster with a phenom-type cpu,
just because the HT link is much faster, and the IGP has to access
memory through this link.


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