Hyper-Threading BIOS changes and Windows Hibernation

[BonzaiDuck]

I'm coming from a current thread about pros/cons of upgrading from 2500K to 4790K (which see . . . ) The topic of Sandy Bridge overclocks arose, and I noted that my systems had HT enabled so my clocks were probably a tad more modest than those touted by others. And I mentioned that I might try an experiment today and disable HT.

[Now at this point, I'll say this thread, having come from another mentioned above, is going to lead to a thread in the HTPC forum, because my experiment led to two issues.]

My 2700K system will sleep after two hours and then hibernate after a third hour. So to make the BIOS change, I switched it on, and went directly into BIOS to disable HT.

When it began to boot into Windows beginning with the "Resuming Windows" screen, it blue-screened. The BSOD didn't even remain on the monitor long enough to read key information, and the system simply shut down -- turned off.

Am I to assume that this occurred because the system emerged from hibernation -- loading a large amount of data from disk -- with programs expecting to run under "threads" that were no longer available because HT had been disabled?

Of course, restarting the system brought up "Starting Windows," the usual menu with an option to start windows normally -- and all was then copacetic.

Now . . . . let me start that HTPC thread . . If I can persist toward the objective, I can come back here and link it.

And so . . . . Here it is:

http://forums.anandtech.com/showthread.php?p=37396744#post37396744

 

[zir_blazer]

Hibernation works by saving the RAM content to the Hard Disk. Since disabling Hyper Threading effectively means that Windows would see 4 Threads instead of 8, what you did is changed the underlying Hardware on a method that usually relies on it not changing at all.

 

[BonzaiDuck]

Hibernation works by saving the RAM content to the Hard Disk. Since disabling Hyper Threading effectively means that Windows would see 4 Threads instead of 8, what you did is changed the underlying Hardware on a method that usually relies on it not changing at all.

That's what I figured. If I'd taken more time -- been more patient -- I would've restarted from Hibernation, and then simply restarted it to enter BIOS and make the change only after the restart.

It was my guess also, but I thought I'd snag a second opinion. Plugging into these forums over so many years makes it convenient.

All I can say -- is . . . . Thanks!