NUMCPUVPS settings for a four-processor server

I'm migrating two Informix database servers to a Sun Ultra E4002 with 1.5 GBytes of memory and 4CPUs. One server is heavily-used and performance is optimal, the other is lightly used. I am planning to set up the heavily-used server with NUMCPUVPS=3 (one less than the actual number of processors) as per various recommendations, and leaving the other server with NUMCPUVPS=1. Anyone have any other views about NUMCPUVPS settings, and about the use of processor affinity? Thanks Neil Truby Chase Manhattan Bank Bournemouth, UK neil.truby@chase.com P.S. I know that I would probably optimise performance by having a single server with multiple databases; however for reasons outside my control this has been ruled out.