After the initial possible success of disabling Speedstep, I decided to re-enable Speedstep and sure enough, the reboots were seen again. I also tried to adjust the Windows 7 power settings to 100%/Performance, but to no avail. The informal causal relationship appears to be if the CPU frequency is changing, Skyrim does not like it. Even under heavy load, with Speedstep enabled, I see frequency jumps from 1600MHz to 3700MHz varying for each core and voltage jumps from 0.966V to 1.281V. It appears Skyrim just does not like this behavior.
|Chart showing the CPU Frequency and Voltage fluctuations under load with Speedstep enabled.|
With Speedstep disabled, we now have a steady 3700MHz for each core and voltage at a steady 1.276V (varying slightly, but only by a few fractions).
|Chart showing the CPU Frequency and Voltage with Steepstep disabled.|
|HWInfo64 showing a steady clock on all four cores even in idle|
|CPU-Z CPU information|
If you want to try this, these are the items in the BIOS that I set to [Disabled] to turn off Speedstep:
CPU Enhanced Halt (C1E)
C3/C6 State Support
CPU EIST Function
Below is a screenshot of the BIOS screen where the settings are disabled marked in clumsy red arrows. Note that this was stolen from a website so the clock ratio and frequency are not mine (WOW!):
|Change the marked items to disabled to turn off Speedstep|
Note: I also increased the memory timing from 666.7MHz to 800MHz which gives us 1600MHz on the FSB.