As I've been saying for ages about RAM for the A600, it's better to have slow RAM than none at all. Given the rarity of A600 accelerators, PCMCIA SRAM cards are the best option. SysInfo even reports my system to be a tiny bit faster with PCMCIA Fast RAM than without.
The PCMCIA speed bottleneck is more of an issue for A1200s, but with the A600's plain 68000, RAM in that slot is more than adequate.
