Hey, in case anyone wants a work around I created a guide on how to automatically enable SST after startup, or sleep.
Tested and working on my 9550, let me know if you encounter any problems
By the way, Speed Shift has a nifty option built in called Energy Performance Preference (EPP). Once Speed Shift is enabled, you can set EPP between "max performance" and "energy savings." I would guess most systems would come from Dell (and others) with an EPP set for "medium" performance.
Simply writing to MSR 0x770 does not allow one to change EPP settings.
- ThrottleStop 8.3x provides direct access to EPP settings in the window labeled "Turbo Power Limits". That is the easiest workaround until Dell "updates" the BIOS
- I tried changing the EPP to "max performance" (EPP=0) via powercfg (and via an edited control panel>hardware and sound.power options...); both display updated "dummy" variables but don't actually execute any changes. So presumably EPP changes require writing to MSR_HWP_REQUEST (MSR 0x774)
Setting EPP to 255 makes the system super laggy. Setting EPP to 0 makes the system significantly more snappy than it was without Speed Shift (or with Speed Shift enabled and EPP simply set at factory "medium" performance).
Would be great to finally see speed shift, it's been nearly a year now Dell surely you could have enabled it on your premium laptop line by now?
While I'm on the topic of stuff that could be done there's also the 4K screen flickering that was introduced in BIOS 1.2.10 and seems to have persisted in versions since. Fix this too please!
SpeedShift may be helpful for improved battery life under light load conditions. This would be a great system to support in an updated Dell BIOS