rick, u should try the following, as 3.0 isnt very high for the parts u have:
CPU CLOCK: 180x20 (3.6 Ghz)
(leave all other voltages stock)
Multiplier: (select 3.00 for your board)
and gradually move the CPU CLOCK towards 200!
805's dont scale well with voltage anyway, not nearly as well as the 65nm. If you aren't stable with 1.5vcore @ 4ghz, then you probably won't be able to ever get there.
Certain motherboards are way more tolerant of running 533FSB cpus at 800FSB than others. When I had an 805 in my folding rig it could 4ghz with a P5LD2 @ 1.48vcore, But could only do 3.9ghz on a Gigbyte 945P-S3 (@ 1.52vcore). Obviously, those are identical chipsets, which likely means the root is in the BIOS itself.