Robert Hanson wrote:
... and that if I upgrade to a SMP kernel on this machine that I will have no problem on a single processor machine/motherboard and HT will then be enabled?
I "seem to" recall posts on this list recently where people were "disabling" HT on their multi-processor Intel boxen because of problems.
For the most part, it is safe to run the UP or the SMP kernel on any machine with or without HT and/or multiple CPUs.
In some rare cases, one kernel or the other will not work as expected (ie. at all) and you might have to supply some boot parameters like noacpi etc. If you do have a problem though, just reboot into the other kernel.
Other people have summarised HT. If you can afford to test it (on a live system) turn it off in the BIOS to be safe (or ignore it and use the UP kernel).
If you do have multiple CPUs or a yet to be released dual core CPU then you probably want to use the SMP kernel or you have hardware sitting idle.
Some poorly written drivers don't like SMP. Everything that comes standard with CentOS should be SMP safe but if you start adding 3rd part drivers, watch out.
John.