On Mon, 3 Sep 2007, Roelof van der Kleij wrote:
> Here is a redhat bugzilla entry about this problem:
> https://bugzilla.redhat.com/show_bug.cgi?id=239931
>> Some 64 bit kernel / bios combinations have problems with >= 4 Gb of
>> memory. If you have that, try it with only 2 Gb of memory installed. If
>> this is your problem, try playing with memory mapping bios settings.  In
>> my case, I ran into it with an Intel DQ965GFE motherboard after a bios
>> upgrade.

This was indeed the problem. I have 4GB RAM on the system. I'm now passing 
'mem=3G' as a kernel parameter for a temporary workaround, and the system 
boots up at the expected speed.

Very many thanks :)

Mark