What kind of video processor is provided by the iBook models? Which models can support an external display? What is the maximum resolution supported?

Some iBook models cannot support an external display at all. Officially, iBook models that can support an external display only can "mirror" the contents of the internal display on an external one. However, many are capable of using an external display in dual or "extended desktop mode", Apple just blocked the capability in firmware to protect sales of more expensive Macs.

Information regarding the video system in each iBook model is provided on the specs page for each system. However, for your convenience, this information also is provided in this handy chart below:

iBook	Video	Capability	Max. Res.
G3/300 (Clamshell)	4 MB Rage Mobility	None	N/A
G3/366 SE (Clamshell)	4 MB Rage Mobility	None	N/A
G3/366 (FW/Clamshell)	8 MB Rage Mobility	Mirroring†	800x600†
G3/466 SE (FW/Clamshell)	8 MB Rage Mobility	Mirroring†	800x600†
G3/500 (Dual USB)	8 MB Rage Mobility 128	Mirroring	1024x768
G3/500 (Late 2001)	8 MB Rage Mobility 128	Mirroring	1024x768
G3/600 (Late 2001)	8 MB Rage Mobility 128	Mirroring	1024x768
G3/600 14" (Early 2002)	8 MB Rage Mobility 128	Mirroring	1024x768
G3/600 (16 VRAM)	16 MB Mobility Radeon	Mirroring*	1024x768
G3/700 (16 VRAM)	16 MB Mobility Radeon	Mirroring*	1024x768
G3/700 14" (16 VRAM)	16 MB Mobility Radeon	Mirroring*	1024x768
G3/700 (16 VRAM)	16 MB Mobility Radeon 7500	Mirroring*	1024x768
G3/800 (32 VRAM)	32 MB Mobility Radeon 7500	Mirroring*	1024x768
G3/800 14" (32 VRAM)	32 MB Mobility Radeon 7500	Mirroring*	1024x768
G3/800 (Early 2003)	32 MB Mobility Radeon 7500	Mirroring*	1024x768
G3/900 (Early 2003)	32 MB Mobility Radeon 7500	Mirroring*	1024x768
G3/900 14" (Early 2003)	32 MB Mobility Radeon 7500	Mirroring*	1024x768
G4/800 12" (Original)	32 MB Mobility Radeon 9200	Mirroring*	1024x768
G4/933 14" (Original)	32 MB Mobility Radeon 9200	Mirroring*	1024x768
G4/1.0 14" (Original)	32 MB Mobility Radeon 9200	Mirroring*	1024x768
G4/1.0 12" (Early 2004)	32 MB Mobility Radeon 9200	Mirroring*	1024x768
G4/1.0 14" (Early 2004)	32 MB Mobility Radeon 9200	Mirroring*	1024x768
G4/1.2 14" (Early 2004)	32 MB Mobility Radeon 9200	Mirroring*	1024x768
G4/1.2 12" (Late 2004)	32 MB Mobility Radeon 9200	Mirroring*	1024x768
G4/1.33 14" (Late 2004)	32 MB Mobility Radeon 9200	Mirroring*	1024x768
G4/1.33 12" (Mid-2005)	32 MB Mobility Radeon 9550	Mirroring*	1024x768
G4/1.42 14" (Mid-2005)	32 MB Mobility Radeon 9550	Mirroring*	1024x768

The video system in each iBook model cannot be upgraded.

† These systems can mirror the contents of the internal display on a television or projector via composite video out using the A/V port. Each cannot support a second monitor.

* The underlying hardware in these systems is capable of using an external display in dual or "extended desktop mode", Apple just blocked the capability in firmware to protect sales of more expensive Macs. Unsupported third-party hacks are available.