neptune: ~3 years old and pretty slow.  until the 430hx, it was
the only way to build a multi-P5 system, though.

triton (430fx): ~2 years old, and pretty fast.  it introduced support
for PB cache and EDO, and had much improved memory and PCI interfaces.
it also frequently comes with the PIIX eide controller, which is quite
fast and capable of busmastering.  it's uniprocessor-only, and doesn't
support parity, though.

triton II (430hx): inside a year old, and a little faster than the 430fx.
it mainly just tweaked, with a little better buffering and memory timings.
it also supports error detection and correction and multiprocessors.

triton II (430vx): same age as the 430hx, but mostly inferior.  it doesn't
provide quite as agressive buffering, and has slower EDO timings.  its
only possible advantage is that it supports SDRAM.  but in the presence of
cache, SDRAM provides little benefit to most programs, so...

just for completeness:

Orion: older P6 chipset, which was pathologically buggy for a long time.
reports are that it's fixed now, but...  it offers 4-way multiprocessor
support as well as interleaved FPM.

Natoma: newer P6 chipset, which seems to work quite well, and does EDO.
it's limited to 2x multi, though, and does no interleaving.

there are a couple non-Intel P5 and P6 chipsets, but they never seemed
to ship in much quantity...