O 8.0.5 SGA size HPUX 11

Greetings.
I have been receiving some conflicting information and was hoping someone could shed some light on the issue.

We have an Oracle 8.0.5 database (32 bit) running on an HPUX 11.0 server (10 way CPU, 8 Gig RAM). I have been told that the maximum size for the SGA can be around 1.7 gigs or so, due to the 32 bit architecture of the database.

Here's the part I don't follow:
I have been also told that the sum of the SGA sizes of ALL INSTANCES running on the box must be under or at 1.7 gigs. This seems very strange to me. My thinking is that the HPUX kernel will assign a 4 gig virtual address space (2 gig?) to each process in its process table. I'm not a unix programmer, so I can't confirm, though. It just seems like I should be able to crank up two or more databases, each with an SGA of 1.7 gigs if I wanted.

I've been told it won't work.

1. Could this be true? Have others seen it?
2. If so, is this an Oracle thing? An HP thing?

Any input would be greatly appreciated.
Thanks,
Dave

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