Here is a boot of my Dell PowerEdge 2200 dual Pentium II. It works with bsd.i386 but not with bsd.mp.i386.

i386;OpenBSD 3.5-current (GENERIC) #33: Wed Jun 9 12:40:16 MDT 2004;Dell PowerEdge 2200, dual PII 300MHz, 128Mb, ahc;No problems
i386;OpenBSD 3.5-current (GENERIC.MP) #18: Wed Jun 9 12:40:26 MDT 2004;Dell PowerEdge 2200, dual PII 300MHz, 128Mb, ahc;Interrupts don't appear to work causing ahc to keep spitting out error messages.

boot>
booting hd0a:/bsd.i386: /-\|/4817276-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|+857748 [52+223104/-\|/-\|/-\|/+201361-\|/-\|/-\|/]=0x5d13cc
entry point at 0x100120

[ using 424892 bytes of bsd ELF symbol table ]
Copyright (c) 1982, 1986, 1989, 1991, 1993
The Regents of the University of California. All rights reserved.
Copyright (c) 1995-2004 OpenBSD. All rights reserved. http://www.OpenBSD.org

OpenBSD 3.5-current (GENERIC) #33: Wed Jun 9 12:40:16 MDT 2004
deraadt@i386.openbsd.org:/home/staff/deraadt/src/sys/arch/i386/compile/GENERIC
cpu0: Intel Pentium II ("GenuineIntel" 686-class, 512KB L2 cache) 299 MHz
cpu0: FPU,V86,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,P GE,MCA,CMOV,MMX
real mem = 133799936 (130664K)
avail mem = 115593216 (112884K)
using 1658 buffers containing 6791168 bytes (6632K) of memory
mainbus0 (root)
bios0 at mainbus0: AT/286+(a2) BIOS, date 07/23/98, BIOS32 rev. 0 @ 0xf73aa
pcibios0 at bios0: rev. 2.1 @ 0xf72c0/0x1160
pcibios0: PCI BIOS has 5 Interrupt Routing table entries
pcibios0: PCI Exclusive IRQs: 9 11
pcibios0: no compatible PCI ICU found
pcibios0: Warning, unable to fix up PCI interrupt routing
pcibios0: PCI bus #0 is the last bus
bios0: ROM list: 0xc0000/0x8000 0xc8000/0x5800
cpu0 at mainbus0
pci0 at mainbus0 bus 0: configuration mode 1 (bios)
pchb0 at pci0 dev 0 function 0 "Intel 82441FX" rev 0x02
"Intel 82375EB EISA" rev 0x15 at pci0 dev 13 function 0 not configured
dc0 at pci0 dev 14 function 0 "Lite-On PNIC-II" rev 0x25: irq 9, address 00:c0:f0:75:f3:47
dcphy0 at dc0 phy 31: internal PHY
ahc1 at pci0 dev 18 function 0 "Adaptec AHA-2940U2 U2" rev 0x00: irq 11
scsibus0 at ahc1: 16 targets
sd0 at scsibus0 targ 0 lun 0: <QUANTUM, VIKING II 4.5WLS, 3506> SCSI2 0/direct fixed
sd0: 4350MB, 8338 cyl, 5 head, 213 sec, 512 bytes/sec, 8910423 sec total
vga1 at pci0 dev 20 function 0 "ATI Mach64 VT" rev 0x40
wsdisplay0 at vga1: console (80x25, vt100 emulation)
wsdisplay0: screen 1-5 added (80x25, vt100 emulation)
eisa0 at mainbus0
eisa0: can't map I/O space for slot 15
isa0 at mainbus0
isadma0 at isa0
pckbc0 at isa0 port 0x60/5
pckbd0 at pckbc0 (kbd slot)
pckbc0: using irq 1 for kbd slot
wskbd0 at pckbd0: console keyboard, using wsdisplay0
pcppi0 at isa0 port 0x61
midi0 at pcppi0: <PC speaker>
sysbeep0 at pcppi0
lpt0 at isa0 port 0x378/4 irq 7
npx0 at isa0 port 0xf0/16: using exception 16
pccom0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo
pccom0: console
pccom1 at isa0 port 0x2f8/8 irq 3: ns16550a, 16 byte fifo
biomask fd65 netmask ff65 ttymask ffe7
pctr: 686-class user-level performance counters enabled
mtrr: Pentium Pro MTRR support
ahc1: target 0 using 16bit transfers
ahc1: target 0 synchronous at 40.0MHz, offset = 0x1f
dkcsum: sd0 matched BIOS disk 80
root on sd0a
rootdev=0x400 rrootdev=0xd00 rawdev=0xd02
Automatic boot in progress: starting file system checks.
/dev/rsd0a: file system is clean; not checking
setting tty flags
machdep.allowaperture: 0 -> 2
starting network
Internet Software Consortium DHCP Client 2.0pl5-OpenBSD
Listening on BPF/dc0/00:c0:f0:75:f3:47
Sending on BPF/dc0/00:c0:f0:75:f3:47
Sending on Socket/fallback/fallback-net
DHCPREQUEST on dc0 to 255.255.255.255 port 67
DHCPREQUEST on dc0 to 255.255.255.255 port 67
DHCPREQUEST on dc0 to 255.255.255.255 port 67
DHCPDISCOVER on dc0 to 255.255.255.255 port 67 interval 1
DHCPDISCOVER on dc0 to 255.255.255.255 port 67 interval 1
DHCPDISCOVER on dc0 to 255.255.255.255 port 67 interval 2
DHCPDISCOVER on dc0 to 255.255.255.255 port 67 interval 2
DHCPDISCOVER on dc0 to 255.255.255.255 port 67 interval 5
DHCPDISCOVER on dc0 to 255.255.255.255 port 67 interval 13
DHCPOFFER from 192.168.0.1
DHCPREQUEST on dc0 to 255.255.255.255 port 67
DHCPACK from 192.168.0.1
New Network Number: 192.168.0.0
New Broadcast Address: 192.168.0.255
bound to 192.168.0.109 -- renewal in 21600 seconds.
starting system logger
starting rpc daemons:.
savecore: no core dump
checking quotas: done.
building ps databases: kvm dev.
clearing /tmp
starting pre-securelevel daemons:.
setting kernel security level: kern.securelevel: 0 -> 1
creating runtime link editor directory cache.
preserving editor files
starting network daemons: sendmail inetd sshd.
starting local daemons:.
standard daemons: cron.
Wed Jun 9 08:24:36 CDT 2004
Jun 9 08:24:44 kla login: ROOT LOGIN (root) ON ttyC0
Jun 9 08:24:49 kla reboot: rebooted by root
/etc/rc.shutdown in progress...
/etc/rc.shutdown complete.
Jun 9 08:24:51 kla syncing disks... done
rebooting...
boot>
booting hd0a:bsd.mp.i386: |/-\|4877816/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-\|/-+861624 [58+225392\|/-\|/-\|/-\|+203454/-\|/-\|/-\|]=0x5e20b8
entry point at 0x100120

[ using 429320 bytes of bsd ELF symbol table ]
Copyright (c) 1982, 1986, 1989, 1991, 1993
The Regents of the University of California. All rights reserved.
Copyright (c) 1995-2004 OpenBSD. All rights reserved. http://www.OpenBSD.org

OpenBSD 3.5-current (GENERIC.MP) #18: Wed Jun 9 12:40:26 MDT 2004
deraadt@cvs.openbsd.org:/home/staff/...ile/GENERIC.MP
cpu0: Intel Pentium II ("GenuineIntel" 686-class, 512KB L2 cache) 299 MHz
cpu0: FPU,V86,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,P GE,MCA,CMOV,MMX
real mem = 133799936 (130664K)
avail mem = 115523584 (112816K)
using 1658 buffers containing 6791168 bytes (6632K) of memory
mainbus0 (root)
bios0 at mainbus0: AT/286+(a2) BIOS, date 07/23/98, BIOS32 rev. 0 @ 0xf73aa
pcibios0 at bios0: rev. 2.1 @ 0xf72c0/0x1160
pcibios0: PCI BIOS has 5 Interrupt Routing table entries
pcibios0: PCI Exclusive IRQs: 9 11
pcibios0: no compatible PCI ICU found
pcibios0: Warning, unable to fix up PCI interrupt routing
pcibios0: PCI bus #0 is the last bus
bios0: ROM list: 0xc0000/0x8000 0xc8000/0x5800
mainbus0: Intel MP Specification (Version 1.4) (DELL POWEREDGE )
cpu0 at mainbus0: apid 1 (boot processor)
cpu0: Intel Pentium II ("GenuineIntel" 686-class, 512KB L2 cache) 299 MHz
cpu0: FPU,V86,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,P GE,MCA,CMOV,MMX
cpu0: calibrating local timer
cpu0: apic clock running at 66 MHz
cpu1 at mainbus0: apid 0 (application processor)
cpu1: Intel Pentium II ("GenuineIntel" 686-class, 512KB L2 cache) 299 MHz
cpu1: FPU,V86,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,P GE,MCA,CMOV,MMX
mpbios: bus 0 is type PCI
mpbios: bus 1 is type EISA
ioapic0 at mainbus0 apid 2 (I/O APIC)
ioapic0: pa 0xfec00000, version 11, 16 pins
pci0 at mainbus0 bus 0: configuration mode 1 (bios)
pchb0 at pci0 dev 0 function 0 "Intel 82441FX" rev 0x02
"Intel 82375EB EISA" rev 0x15 at pci0 dev 13 function 0 not configured
dc0 at pci0 dev 14 function 0 "Lite-On PNIC-II" rev 0x25pci_intr_map: bus 0 dev 14 func 0 pin 1; line 9
pci_intr_map: no MP mapping found
isa_intr_establish: no MP mapping found
: irq 9, address 00:c0:f0:75:f3:47
dcphy0 at dc0 phy 31: internal PHY
ahc1 at pci0 dev 18 function 0 "Adaptec AHA-2940U2 U2" rev 0x00pci_intr_map: bus 0 dev 18 func 0 pin 1; line 11
pci_intr_map: no MP mapping found
isa_intr_establish: no MP mapping found
: irq 11
scsibus0 at ahc1: 16 targets
sd0 at scsibus0 targ 0 lun 0: <QUANTUM, VIKING II 4.5WLS, 3506> SCSI2 0/direct fixed
sd0: 4350MB, 8338 cyl, 5 head, 213 sec, 512 bytes/sec, 8910423 sec total
vga1 at pci0 dev 20 function 0 "ATI Mach64 VT" rev 0x40
wsdisplay0 at vga1: console (80x25, vt100 emulation)
wsdisplay0: screen 1-5 added (80x25, vt100 emulation)
eisa0 at mainbus0
eisa0: can't map I/O space for slot 15
isa0 at mainbus0
isadma0 at isa0
pckbc0 at isa0 port 0x60/5
pckbd0 at pckbc0 (kbd slot)
isa_intr_establish: no MP mapping found
pckbc0: using irq 1 for kbd slot
wskbd0 at pckbd0: console keyboard, using wsdisplay0
pcppi0 at isa0 port 0x61
midi0 at pcppi0: <PC speaker>
sysbeep0 at pcppi0
lpt0 at isa0 port 0x378/4 irq 7
isa_intr_establish: no MP mapping found
npx0 at isa0 port 0xf0/16: using exception 16
pccom0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo
isa_intr_establish: no MP mapping found
pccom0: console
pccom1 at isa0 port 0x2f8/8 irq 3: ns16550a, 16 byte fifo
isa_intr_establish: no MP mapping found
biomask fd65 netmask ff65 ttymask ffe7
ioapic0: enabling
pctr: 686-class user-level performance counters enabled
mtrr: Pentium Pro MTRR support
ahc1: Timedout SCB already complete. Interrupts may not be functioning.