[CentOS] CentOS 5.7 - occasional lockup

Using Core i7 boxes with CentOS 5.7, have experienced lockups on half of a
handful of units over a couple months.  They are Logic Supply Mini-ITX
model KR960 with Core i7-3610QE.

A couple weeks ago I enabled self-reboot on kernel panic (echo 10 >
/proc/sys/kernel/panic) on all units, and had another unit lock up rather
than reboot itself.

I'm not sure how to pursue the problem.

Doing "yum update kernel*" shows there's a newer kernel,
2.6.18-371.1.2.el5 - I'm using the stock 2.6.18-274.el5 kernel now -
where's a change log of the differences so I can see if there are driver
or kernel updates that might seem to apply?

I don't know if setting up kdump would help since it doesn't even seem to
be getting to the point where the kernel is trying to handle a panic.

What else might I try?