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Elite Member
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FutureMark的字典好像也蠻好用的
http://www.futuremark.com/community...abulary/?page=1
引用:
AGP Memory (AGP Aperture)
A feature of all AGP specifications. An AGP graphics adapter can use part of the system memory to store data and/or directly render from. Once it has been set by the operating system, the amount of memory allocated to the use of AGP memory is then dynamic and changes as according to use by the graphics adapter and application using it. The maximum size of memory that can be "sidelined" is determined by the AGP Aperture value in the motherboard BIOS.
So why not just use the normal system memory? Pages that are allocated to AGP memory cannot be paged to the hard drive (swapped into the virtual memory/swap file) and the addresses for each page are stored in a table that can be accessed very easily by the Northbridge chip. All of this helps to increase the performance of read/writes of data stored in the AGP memory.
The graphics adapter can access the contents of the AGP memory by several methods:
DMA (Direct Memory Access): the graphics adapter is not permitted to render directly from the AGP memory but it can take data from it as and when it needs to. This is currently the standard mode used as virtually all graphics cards have sufficient local memory to store the data it needs.
DIME (Direct Memory Execute): the graphics adapter must always render directly from the AGP memory in this mode. Considering that using the local memory is far faster than the AGP memory for rendering, this is only used with onboard graphics adapters that are forced (by design) to use system memory instead of having their own local memory.
DIMEL (Direct Memory Execute and Local): the graphics adapter can be made to render from either the local or AGP memory. The idea behind this mode is that data that is not going to be needed very often can be left in the AGP memory, whereas frequently accessed data is kept in the local memory. In reality, it is limited in use as graphics cards today can read/write data across the local memory bus so much faster than across the AGP bus that the AGP memory becomes a hindrance rather than a performance aid.
For a particular mode to be used, both the graphics adapter and system (operating system, Northbridge, etc) must support it.
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