J'ai une carte graphique 128MB 8X sur une carte-mère 4x
J'ai trouvé une réponse pour la première partie de ma question il fallait traduire le terme en anglais :
http://support.gateway.com/s/MOTHERBD/s ... adap.shtml
"Frequently Asked Questions
Q: What is Accelerated Graphics Port (AGP) aperture size?
The AGP aperture is a logical memory address range used by the video graphics subsystem. The AGP aperture size is programmed by the BIOS Setup Utility prior to starting to the operating system. The default is 64 megabytes (MB). This is a size that is considered okay for Windows 98. A 256 MB aperture size is added as an option if the operating system has a failure when set to 64 MB.
The programmed size (64 MB or 256 MB) does not represent an actual physical memory size. It represents a range of memory addresses. The graphics controller can use both local (memory on the controller) and computer memory as primary video memory, given the very large video memory size required to efficiently render 3D objects using computer memory. Graphics memory must be physically contiguous. Since Windows allocates memory in random pages, graphics structures rendered in computer memory are not actually physically contiguous. The chipset solves this situation by supporting a memory mapping table called the Graphic Address Remapping Table (GART), and the AGP aperture. GART programming allows memory accesses to the pages within the aperture to be remapped to the physical pages allocated by Windows. "