kernel coredumps with 4GB of ram/SMP? with -current

On my two test (1gb of ram and 512mb of ram) systems if I do reboot -d I
get a kernel crash dump I can read ok (which is what -d is supposed to
do).  On my two systems with 4GB of ram when I do reboot -d it says:
Dumping 3838 MB

Then it sits there.  It doesnt print out any progress like it does with
the systems with smaller amounts of ram.  If I press a space bar it says:
[CTRL-C to abort]

If I let it sit for hours then try pressing the space bar again it has
stopped respondng. In all cases dumpon was run pointing at the first swap
area.

Is anyone with 4GB of ram and -current getting kernel core dumps?  Also
the 4GB systems are XEON 2800mhz if having SMP matters.