Re: [CAD_CAM_EDM_DRO] Imbedded computers

Codesuidae wrote:

>Stephen Wille Padnos wrote:
>
>
>>juan gelt wrote:
>>
>>
>>>is it that you guys crave to run windows on this?
>>>there are a couple real-time os that are nowhere near
>>>so heavy on the graphics....
>>>
>>>
>>It doesn't really matter. It's not the drawing that's the problem, it's
>>the refresh.
>>
>>
>That is unlikely. All video cards, including all on-board cards, have
>dedicated fast video memory that does not affect the CPU.
>

Unfortunately, that's incorrect.
Look at the BIOS on one of those boards some day. There will be an
option for "amount of memory to reserve for video" or something like
that. The Intel 865 (the chip used in most of the boards linked to
earlier) specs explicitly state that video memory is part of system RAM:
"The GMCH does not support a dedicated local graphics memory interface;
it may only be used in a UMA configuration" (UMA stands for Unified
Memory Architecture)

If you install a video card into a machine that has onboard video, then
the scenario you described would hold true, since the onboard video
could be disabled. Not all motherboards with built-in video use a UMA
architecture, but many do, since it reduces system cost (they don't have
to provide special memory on the motherboard - you pay for it when you
buy a DIMM)

- Steve