The problem is not IDS 7.3x, the problem is that S.O. is 32 bits. The maximum size shared memory is about 1.7 GB.
You can assign this value in SHMVIRTSIZE, then define SHMADD, for the memory increase.
Or change the S.O. to 64 bits.
Excuse me, but a thing is the maximum size of the segment of shared memory and another is the maximum size of a chunk. The size of the chunk depends on the version of IDS, not if this in 32 or 64 bits The maximum size of the first segment of shared memory, in a system of 32 bits, is
of approximately 1.7GB, then the IDS is able increase so much as the memory physical of the system be permitted it.
If the problem is the size of the chunks, alone will be able them to create of a maximum of 2GB, in IDS version 7. x