1 GB is the entire Zorro III space isnt it?
The most RAM I ever had in an A3000 was:
Motherboard = 16 + 2
Accelerator = 128
DKB3128 = 128
Total = 274 Mbytes
I did have more in my subsequent A4000 because it had a Fastlane SCSI card with another 64Mbytes.
But I never used anywhere near that much RAM. I doubt any software ever used more than 64Mbytes.