I went to my local PC junk store and bought a bunch of old ISA video cards with chips that looked the same as the ones in Amigas (I was upgrading some A2091 cards to 2MB as well as a A600 1MB card) I got lucky they all worked. I would count the pins and just see if you can find some old cards and just try them. Try to get faster chips though if you can.
As noted above, some A3000's shipped with 1MByte of FAST memory in DIP package, waiting to be transplanted into the sockets for CHIP RAM, once more FAST RAM was installed. Those FAST memory sockets are the U850D-U857D 20 pin DIP places, Bank 0. This bank is electrically mapped to Bank 0 U850-U857, 20 pin ZIP sockets. As a result, one can make a three megabyte A3000 configuration by putting 256Kbit x 4 chips into the FAST RAM DIP sockets without buying ZIPs. Or a six meg setup, using 1MBit x 4 chips. The DIP FAST sockets cannot be used with the ZIP sockets all together, as the two Bank 0 areas are basically pinned to each other (as noted by the same component numbers, one set with a D for DIP). One could have 4MBytes of DIPs for FAST, then another 12MBytes of FAST in ZIPs placed into Banks 1-3, but not 4MBytes in the DIP area and 16MBytes in all four ZIP banks.
I did not know you could add 4MB of DIPS to the A3000! That is great to know. A 6MB A3000 using cheap DIPS would not be a bad thing...
