I need advice from someone familiar with internal technical details of the Pentium 4 CPU.

The P4 has a circuit which "shuts the CPU off" if a very high temperature is detected. It is automatic and does not involve any software. I suspect that the bus signal THERMTRIP# causes the CPU to drop into a SLEEP or DEEP SLEEP state. My question #1: If the CPU goes into a SLEEP/DEEP-SLEEP state in the midst of normal operation, would I see the following?

(1) Complete absence of any sign of activity other than continued spinning of the hard disks and fans;
(2) Complete nonresponsiveness to any user action (mouse, key presses, even pressing the power-off button uinless held for 5 seconds or longer);
(3) All visible indications (screen display, indicator LEDs) frozen in the exact state occupied at the instant that the SLEEP/DEEP-SLEEP state was entered - in other words, the screen continues to display desktop and application displays (frozen), not a blue, dark, or corrupted screen.

Finally, what circumstances other than an extreme over-temp condition can cause such a switch to SLEEP/DEEP-SLEEP?

Thanks.

Originally Posted by slemaker

I need advice from someone familiar with internal technical details of the Pentium 4 CPU.

The P4 has a circuit which "shuts the CPU off" if a very high temperature is detected. It is automatic and does not involve any software. I suspect that the bus signal THERMTRIP# causes the CPU to drop into a SLEEP or DEEP SLEEP state. My question #1: If the CPU goes into a SLEEP/DEEP-SLEEP state in the midst of normal operation, would I see the following?

(1) Complete absence of any sign of activity other than continued spinning of the hard disks and fans;
(2) Complete nonresponsiveness to any user action (mouse, key presses, even pressing the power-off button uinless held for 5 seconds or longer);
(3) All visible indications (screen display, indicator LEDs) frozen in the exact state occupied at the instant that the SLEEP/DEEP-SLEEP state was entered - in other words, the screen continues to display desktop and application displays (frozen), not a blue, dark, or corrupted screen.

Finally, what circumstances other than an extreme over-temp condition can cause such a switch to SLEEP/DEEP-SLEEP?

Thanks.

Sleep/Deepsleep is usually a function of power management in the bios not internal cpu temp settings, however, the symptoms you describe certainly are indicative of overheating...except for perhaps the screen freezing because in most overheating situations the computer will simply shut off unless that is disabled in the bios...for a thorough read, click here: (copy/paste)
www.intel.com/performance/ resources/briefs/portability.pdf

Thanks. Do you, by any chance, know of a source which explains in some detail just what happens when the CPU is switched to one of the SLEEP/DEEPSLEEP etc. states? I skimmed over the reference you cited and, although it relates these states to the power-management function, it doesn't appear to contain the info I'm seeking. Or did I skim it too quickly and overlook something?

Thanks again.

Originally Posted by slemaker

Thanks. Do you, by any chance, know of a source which explains in some detail just what happens when the CPU is switched to one of the SLEEP/DEEPSLEEP etc. states? I skimmed over the reference you cited and, although it relates these states to the power-management function, it doesn't appear to contain the info I'm seeking. Or did I skim it too quickly and overlook something?

Thanks again.

Well, I suppose it differs by cpu and socket type...what do you have? Most of the product documentation for intel cpu's is here:
http://www.intel.com/design/Pentium4/documentation.htm

you will find some testing utilities here:
http://downloadfinder.intel.com/scri...ting%20Systems

I believe I have all the relevant documentation from the Web site you reference, for both the P4 and the mother board. None of these, unfortunately, gives a functional description or flowchart of the consequences of these sleep states.

Thanks anyway.