rw:comp:amiga:chipset

Released	Acronym and Extended Name	Models that used it
1985	OCS - Original Chipset	A1000, A2000, A500
1990	ECS - Extended Chipset	A3000, A500+, A600, A2000
1992	AGA - Advanced Graphics Architecture	A1200, A4000, CD32

This is the main graphics chip for Amigas.
You can swap 8370 (512KB) and 8372(1024KB) chips whenever/wherever you like. Of course memory limits are tied to the chip.
You can't swap an 8375 (2MB) for a 512/1024KB chip and get more memory. There are other changes needed to for the large memory addresses.
Format/package - (84) contact PLCC Fat Agnus (named Fat Lady on most Amiga 2000 motherboards) 8370; 8371; 8372; 8372A; 8372AB; 8372B; 8375
8372B and 8375 - SuperFat Agnus with 2MB, hard to find, grab it if you can get it, I think this is the standard chip for all ECS machines
Agnus became Alice in the A4000/A1200

Chip Name	Chip Number	Part Number	Used In
Agnus (512K)	8361	252125-01	A1000 (NTSC), A2000A (NTSC)
Agnus (512K)	8361 R3		A1000(NTSC), A2000A(NTSC)
Agnus (512K)	8367	252362-01	A1000 (PAL), A2000A (PAL)
Agnus (512K)	8370	318070-01	A500 (NTSC), A2000 (NTSC), can be swapped for an 8372
Agnus (512K)	8371	318071-01	A500 (PAL), A2000 (PAL)
Agnus (1MB)	8372	318069-02	A500 (PAL), A2000 (PAL) Regular Type
Agnus (1MB)	8372A	318069-02	A500 (PAL), A2000 (NTSC), can be swapped for an 8370
Agnus (1MB)	8372A	318069-029	A500 (PAL), A2000 (PAL) (changed after some damage)
Agnus (2MB)	8372AB	318069-03	A3000 (PAL), A3000T (PAL)
Agnus (2MB)	8372B	318069-03	MegAChip (NTSC)
Agnus (2MB)	8375 R0	318069-18	A500+ (PAL), A600 (PAL)
Agnus (1MB)	8375 / 8375 R1	318069-16	A500 (PAL), A2000 (PAL)
Agnus (2MB)	8375 R2	318069-10	A500+ (PAL), A600 (PAL)
Agnus (2MB)	8375	318069-11	A500+(NTSC) and A600(NTSC)
Agnus (1MB)	8375	318069-17	A500 (NTSC), A2000 (NTSC) in rev 6.4
Agnus (2MB)	8375	318069-19	A3000 (NTSC), A3000T (NTSC)
Agnus (2MB)	8375	390544-01	A500+ (PAL), A600 (PAL)
Agnus (2MB)	8375	390544-02	A500+ (NTSC), A600 (NTSC)