[shep]

I think your system will support the amd64 platform.
I am running 4.7/amd64 on mine without issues (per Jggimi's post that follows mine is patched to stable)

$ dmesg
OpenBSD 4.7 (GENERIC.MP) #0: Tue May 25 15:28:49 PDT 2010
jsh@Atom.home.yak:/usr/src/sys/arch/...ile/GENERIC.MP
real mem = 2135060480 (2036MB)
avail mem = 2068758528 (1972MB)
RTC BIOS diagnostic error 80<clock_battery>
mainbus0 at root
bios0 at mainbus0: SMBIOS rev. 2.4 @ 0xe3590 (23 entries)
bios0: vendor Intel Corp. version "LF94510J.86A.0171.2009.0403.0118" date 04/03/2009
bios0: Intel Corporation D945GCLF2
acpi0 at bios0: rev 0
acpi0: tables DSDT FACP APIC WDDT MCFG ASF! HPET
acpi0: wakeup devices SLPB(S4) P32_(S4) UAR1(S4) UAR2(S4) PEX0(S4) PEX1(S4) PEX2(S4) PEX3(S4) PEX4(S4) PEX5(S4) UHC1(S3) UHC2(S3) UHC3(S3) UHC4(S3) EHCI(S3) AC9M(S4) AZAL(S4)
acpitimer0 at acpi0: 3579545 Hz, 24 bits
acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat
cpu0 at mainbus0: apid 0 (boot processor)
cpu0: Intel(R) Atom(TM) CPU 330 @ 1.60GHz, 1596.26 MHz
cpu0: FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,P GE,MCA,CMOV,PAT,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,S S,HTT,TM,SBF,SSE3,MWAIT,DS-CPL,TM2,CX16,xTPR,NXE,LONG
cpu0: 512KB 64b/line 16-way L2 cache
cpu0: apic clock running at 133MHz
cpu1 at mainbus0: apid 2 (application processor)
cpu1: Intel(R) Atom(TM) CPU 330 @ 1.60GHz, 1596.00 MHz
cpu1: FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,P GE,MCA,CMOV,PAT,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,S S,HTT,TM,SBF,SSE3,MWAIT,DS-CPL,TM2,CX16,xTPR,NXE,LONG
cpu1: 512KB 64b/line 16-way L2 cache
cpu2 at mainbus0: apid 1 (application processor)
cpu2: Intel(R) Atom(TM) CPU 330 @ 1.60GHz, 1596.01 MHz
cpu2: FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,P GE,MCA,CMOV,PAT,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,S S,HTT,TM,SBF,SSE3,MWAIT,DS-CPL,TM2,CX16,xTPR,NXE,LONG
cpu2: 512KB 64b/line 16-way L2 cache
cpu3 at mainbus0: apid 3 (application processor)
cpu3: Intel(R) Atom(TM) CPU 330 @ 1.60GHz, 1596.01 MHz
cpu3: FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,P GE,MCA,CMOV,PAT,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,S S,HTT,TM,SBF,SSE3,MWAIT,DS-CPL,TM2,CX16,xTPR,NXE,LONG
cpu3: 512KB 64b/line 16-way L2 cache
ioapic0 at mainbus0: apid 2 pa 0xfec00000, version 20, 24 pins
ioapic0: misconfigured as apic 0, remapped to apid 2
acpihpet0 at acpi0: 14318179 Hz
acpiprt0 at acpi0: bus 0 (PCI0)
acpiprt1 at acpi0: bus 4 (P32_)
acpiprt2 at acpi0: bus 1 (PEX0)
acpiprt3 at acpi0: bus -1 (PEX1)
acpiprt4 at acpi0: bus 2 (PEX2)
acpiprt5 at acpi0: bus 3 (PEX3)
acpiprt6 at acpi0: bus -1 (PEX4)
acpiprt7 at acpi0: bus -1 (PEX5)
acpicpu0 at acpi0
acpicpu1 at acpi0
acpicpu2 at acpi0
acpicpu3 at acpi0
acpibtn0 at acpi0: SLPB
pci0 at mainbus0 bus 0
pchb0 at pci0 dev 0 function 0 "Intel 82945G Host" rev 0x02
vga1 at pci0 dev 2 function 0 "Intel 82945G Video" rev 0x02
wsdisplay0 at vga1 mux 1: console (80x25, vt100 emulation)
wsdisplay0: screen 1-5 added (80x25, vt100 emulation)
intagp0 at vga1
agp0 at intagp0: aperture at 0x80000000, size 0x10000000
inteldrm0 at vga1: apic 2 int 16 (irq 11)
drm0 at inteldrm0
azalia0 at pci0 dev 27 function 0 "Intel 82801GB HD Audio" rev 0x01: apic 2 int 22 (irq 9)
azalia0: codecs: Realtek ALC662
audio0 at azalia0
ppb0 at pci0 dev 28 function 0 "Intel 82801GB PCIE" rev 0x01: apic 2 int 17 (irq 255)
pci1 at ppb0 bus 1
ppb1 at pci0 dev 28 function 2 "Intel 82801GB PCIE" rev 0x01: apic 2 int 18 (irq 255)
pci2 at ppb1 bus 2
ppb2 at pci0 dev 28 function 3 "Intel 82801GB PCIE" rev 0x01: apic 2 int 19 (irq 255)
pci3 at ppb2 bus 3
uhci0 at pci0 dev 29 function 0 "Intel 82801GB USB" rev 0x01: apic 2 int 23 (irq 10)
uhci1 at pci0 dev 29 function 1 "Intel 82801GB USB" rev 0x01: apic 2 int 19 (irq 11)
uhci2 at pci0 dev 29 function 2 "Intel 82801GB USB" rev 0x01: apic 2 int 18 (irq 9)
uhci3 at pci0 dev 29 function 3 "Intel 82801GB USB" rev 0x01: apic 2 int 16 (irq 11)
ehci0 at pci0 dev 29 function 7 "Intel 82801GB USB" rev 0x01: apic 2 int 23 (irq 10)
usb0 at ehci0: USB revision 2.0
uhub0 at usb0 "Intel EHCI root hub" rev 2.00/1.00 addr 1
ppb3 at pci0 dev 30 function 0 "Intel 82801BA Hub-to-PCI" rev 0xe1
pci4 at ppb3 bus 4
ath0 at pci4 dev 0 function 0 "Atheros AR5212" rev 0x01: apic 2 int 21 (irq 10)
ath0: AR2414 7.9 phy 4.5 rf2413 5.6, FCC1A, address 00:30:4f:4a:bf:76
pcib0 at pci0 dev 31 function 0 "Intel 82801GB LPC" rev 0x01
pciide0 at pci0 dev 31 function 2 "Intel 82801GB SATA" rev 0x01: DMA, channel 0 configured to native-PCI, channel 1 configured to native-PCI
pciide0: using apic 2 int 19 (irq 11) for native-PCI interrupt
wd0 at pciide0 channel 0 drive 0: <WDC WD5000AACS-19G8B1>
wd0: 16-sector PIO, LBA48, 476940MB, 976773168 sectors
wd0(pciide0:0:0): using PIO mode 4, Ultra-DMA mode 6
atapiscsi0 at pciide0 channel 1 drive 0
scsibus0 at atapiscsi0: 2 targets
cd0 at scsibus0 targ 0 lun 0: <PIONEER, DVD-RW DVR-216D, 1.07> ATAPI 5/cdrom removable
cd0(pciide0:1:0): using PIO mode 4, Ultra-DMA mode 4
ichiic0 at pci0 dev 31 function 3 "Intel 82801GB SMBus" rev 0x01: apic 2 int 19 (irq 11)
iic0 at ichiic0
admtm0 at iic0 addr 0x2d: 47m192
spdmem0 at iic0 addr 0x50: 2GB DDR2 SDRAM non-parity PC2-6400CL5
usb1 at uhci0: USB revision 1.0
uhub1 at usb1 "Intel UHCI root hub" rev 1.00/1.00 addr 1
usb2 at uhci1: USB revision 1.0
uhub2 at usb2 "Intel UHCI root hub" rev 1.00/1.00 addr 1
usb3 at uhci2: USB revision 1.0
uhub3 at usb3 "Intel UHCI root hub" rev 1.00/1.00 addr 1
usb4 at uhci3: USB revision 1.0
uhub4 at usb4 "Intel UHCI root hub" rev 1.00/1.00 addr 1
isa0 at pcib0
isadma0 at isa0
com0 at isa0 port 0x3f8/8 irq 4: ns16550a, 16 byte fifo
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
pmsi0 at pckbc0 (aux slot)
pckbc0: using irq 12 for aux slot
wsmouse0 at pmsi0 mux 0
pcppi0 at isa0 port 0x61
midi0 at pcppi0: <PC speaker>
spkr0 at pcppi0
lpt0 at isa0 port 0x378/4 irq 7
mtrr: Pentium Pro MTRR support
vscsi0 at root
scsibus1 at vscsi0: 256 targets
softraid0 at root
root on wd0a swap on wd0b dump on wd0b