/etc/mk.conf options for optimized binaries

["Patrick Giagnocavo +1.717.201.3366" <patrick_(_at_)_zill_(_dot_)_net>]

I recompiled kernel and userland (with COPTS=-mcpu=v8) on a Sparc-10
and noticed performance improvements.

Is there a list of what the COPTS should be for all Sparc variants,
and all x86 variants?  What is the best option for my Athlon 1700XP
boxes, for instance?

What I would like to hear about are the best COPTS in mk.conf for:

x86:
Athlon XP 
Pentium
PII
PII-Xeon
PIII
Cyrix and VIA

Sun SPARC:
SS10 (supersparc):  use COPTS=-mcpu=v8
Sun5 etc (microsparc)
IPC/IPX/SS2 (to get best performance on these low-end systems)

Can anyone point me to a reference on this?

Cordially

Patrick