I just emerged gentoo-sources and obtained 2.6.13-gentoo-r3.
I copied over my .config from linux-2.6.12-gentoo-r10 then executed

make
make install    #I don't have any modules

When I booted an oops occurred, the output of dmsg is attached
as is my .config.

The .config contains two variables not use in 2.6.13.  I am fairly
sure no harm is done leaving the variables there, but I did a run with
them removed and an oops still occurred.

I think my .config is fairly vanilla.  I do have an SMT intel
processor (dell 5150--/proc/cpuinfo is below).

gottlieb@ajglap ~ $ gcc --version
gcc (GCC) 3.3.6 (Gentoo 3.3.6, ssp-3.3.6-1.0, pie-8.7.8)

gottlieb@ajglap ~ $ /sbin/lspci
0000:00:00.0 Host bridge: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to I/O Controller (rev 02)
0000:00:00.1 System peripheral: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to I/O Controller (rev 02)
0000:00:00.3 System peripheral: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to I/O Controller (rev 02)
0000:00:01.0 PCI bridge: Intel Corporation 82852/82855 GM/GME/PM/GMV Processor to AGP Controller (rev 02)
0000:00:1d.0 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #1 (rev 01)
0000:00:1d.1 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #2 (rev 01)
0000:00:1d.2 USB Controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) USB UHCI Controller #3 (rev 01)
0000:00:1d.7 USB Controller: Intel Corporation 82801DB/DBM (ICH4/ICH4-M) USB2 EHCI Controller (rev 01)
0000:00:1e.0 PCI bridge: Intel Corporation 82801 Mobile PCI Bridge (rev 81)
0000:00:1f.0 ISA bridge: Intel Corporation 82801DBM (ICH4-M) LPC Interface Bridge (rev 01)
0000:00:1f.1 IDE interface: Intel Corporation 82801DBM (ICH4-M) IDE Controller (rev 01)
0000:00:1f.5 Multimedia audio controller: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Audio Controller (rev 01)
0000:00:1f.6 Modem: Intel Corporation 82801DB/DBL/DBM (ICH4/ICH4-L/ICH4-M) AC'97 Modem Controller (rev 01)
0000:01:00.0 VGA compatible controller: nVidia Corporation NV34M [GeForce FX Go5200] (rev a1)
0000:02:01.0 Ethernet controller: Broadcom Corporation BCM4401 100Base-T (rev 01)
0000:02:02.0 Network controller: Broadcom Corporation BCM4309 802.11a/b/g (rev 02)
0000:02:04.0 CardBus bridge: Texas Instruments PCI4510 PC card Cardbus Controller (rev 02)
0000:02:04.1 FireWire (IEEE 1394): Texas Instruments PCI4510 IEEE-1394 Controller

Any help would be appreciated.
thanks,
allan