In contrast, higher-end PC systems of this era can operate 1024 × 768 at 72 Hz with a full 256-color display. 800 × 600 mode is rarely used as it can only operate at a flickering 60 Hz interlaced mode. AGA lacks flicker free higher resolution modes, being only able to display 640 × 480 at 72 Hz flicker-free operation. Workbench in 256 colors is much slower than ECS operation modes for normal application use a workaround is to use multiple screens with different color depths. In practice, the AGA HAM mode is mainly useful in paint programs, picture viewers, and for video playback. Also the lack of a chunky graphics mode is a speed impediment to graphics operations not tailored for planar modes, resulting in ghost artifacts during the common productivity task of scrolling. Apart from the graphics data fetches, AGA still operates on 16-bit data only, meaning that significant bandwidth is wasted during register accesses and copper and blitter operations. Other features added to AGA over ECS are super-hi-res smooth scrolling and 32-bit fast page memory fetches to supply the graphics data bandwidth for 8 bitplane graphics modes and wider sprites.ĪGA is an incremental upgrade, rather than the dramatic upgrade of the other chipset that Commodore had begun in 1988, the Amiga Advanced Architecture chipset (AAA), lacking many features that would have made it competitive with other graphic chipsets of its time. The palette for the AGA chipset has 256 entries from 16,777,216 colors (24-bit), whereas previous chipsets, the Original Chip Set (OCS) and Enhanced Chip Set (ECS), only allow 32 colors out of 4096 or 64 colors in Amiga Extra Half-Brite (EHB mode). This allows for 256 colors in indexed display modes and 262,144 colors (18-bit) in Hold-And-Modify (HAM-8) modes. ĪGA is able to display graphics modes with a depth of up to 8 bits per pixel. The name was later changed to AGA for the European market to reflect that it largely improved the graphical subsystem, and to avoid trademark issues.
Before release AGA was codenamed Pandora by Commodore International.ĪGA was originally called AA for Advanced Architecture in the United States. ( Learn how and when to remove this template message)Īmiga Advanced Graphics Architecture ( AGA) is the third-generation Amiga graphic chipset, first used in the Amiga 4000 in 1992. ( January 2015) ( Learn how and when to remove this template message)
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