Hi Bob
we're talking different things here:
"pre-installed memory size 4 MB": refers too additional sound samples you can install.
"Additional Memory 1024 MB": referes too 2 Dimms you can install to get your sound sample library up too 1GB of additional sounds that you can install.
The rest is self explainatory.
What I was refering to is not in the manual.
George Kay asked Yamaha the question how many MB of wave rom for "all" the sounds in the T2. They said because they are compressed it's hard to come up with a number.
I guess if they were not compressed it would be around 300MB of sound RAM that's what Michel was trying to say.
So we're talking total MB used to create all the sounds in the T2.
I hope this clarifies it for you.

Eric