Nothing on the back of the box saying that it's enhanced when using 1MB (or more):
http://hol.abime.net/1952/boxscan
It does mention "A500/PLUS/AA600/A1200"...
At work so can't listen to the sound but:
Loaded "
Sink or Swim (1993)(Zeppelin)[cr QTX][f level 9][t +5 SCX].adf" using a "
Quickstart A500 1.3 ROM, ECS Agnus, 512 KB Chip RAM + 512 KB Slow RAM" configuration.
Loaded "
Sink or Swim (1993)(Zeppelin)(Disk 1 of 2).ipf" + "
Sink or Swim (1993)(Zeppelin)(Disk 2 of 2).ipf" using a "
Quickstart A1200 Basic non-expanded" configuration.
Took screenshots of the following and compared:
a) the "first title" screen.
b) "Sink or Swim text" screen.
c) "man getting into submarine" screen.
d) "1st level" screen.
Exactly the same results; no visual difference at all
...will compare the sound between the 2 different sets / configurations when I'm home tonight