Just overclock the 3000.. :-P
Have your friend also check what type RAM chips are in there if he can. It's best not to wiggle them around, in case some of the chips develop a bad connection with the sockets.
The A3000 can take two sizes. 256kbitx4 and 1Mbitx4. This is selected with jumpers. The 514400 chips in the eBay link above are 1Mx4. RAM chip sizes are reported in bits, not bytes. There are eight bits per byte, but as you see, not all RAM chips are eight bits wide.
Both chips are four bits wide, and the A3000 has a 32 bit wide data bus, so you need to add both type of chip in sets of eight so that there is a full 32 bits worth of RAM in each bank. The A3000 has 32 ZIP sockets, meaning four banks of eight chips.
Eight 256kbitx4 chips result in 1024kByte of RAM, thus you can fit up to 4MB with the smaller chips.
Eight 1Mbitx4 chips result in 4MByte of RAM, thus you can fit a total of 16MB in there.
Last edited by Jope; 15 June 2016 at 18:54.