IDF 15
That must be the first time I've heard of SST and its impact on energy efficiency. However what Intel describes on slides / in theory and if actual devices in daily life have a longer battery life are two completely different things.
One could say SST mostly did serve Intel's and Microsoft's marketing purposes if you read all those online articles about Speed Shift boosting performance of Skylake CPUs exclusively on Windows 10. I hope this thread helped to demystify this feature and that most of what you read online about...
If your BIOS supports CPPC simply enable this feature in your BIOS settings. Intel's drivers will then automatically enable SST in Windows 10.
Otherwise you could manually enable SST via the IA32_PM_ENABLE MSR (0x700) - which btw. works under Windows 7 / 8 as well. If you don't know what that...
Speed Shift is enabled if the SST label inside the Features box in the System Summary window of HWiNFO64 is green.
I unfortunately can't directly upload screenshots here :( and I'm too lazy to use another image provider ...
I've only tested the new firmware on a ASUS Z170-A board yet and didn't have any problems so far with v3007. ASUS also hasn't removed this version yet from their support page for this particular model. But I'm also not surprised that there're problems with other models since this version...
I can confirm that this is a new feature introduced in the 30xx versions, even though all the revision history shows is "Improve system stability". As usual the changelog ASUS provides sucks ... It seems ASUS made quite some changes under the hood in v30xx as AMIBCP shows.
Just a small update:
it seems ASUS has started to integrate CPPC v2 into their firmware versions. Don't know exactly when they added this feature but firmware version 1801 for the Z170-A didn't have the option while the current version 3007 does. And as expected SST is now enabled in Windows 10...
HWP is not exclusive to Win 10. Intel CPPC drivers are available for Windows 8 / 8.1 as well, at least for some systems (like some Lenovo Thinkpads for example). The standard (non CPPC) Intel / MS processor drivers for desktop Skylakes however do not enable HWP, no matter which version of...
It is true that it's actually the responsibility of the OS and its CPU driver (i.e. MS / Intel) to enable Skylake's Speed Shift / HWP and not the UEFI firmware. So no, there's no firmware support needed for this specific feature to be enabled. That's why HWP just works fine under Linux and can...
Thanks for the info, interesting to see this option inside an actual BIOS setup.
But as said: it's actually not the responsibility of the BIOS / MB to enable HWP (as you can read in Intel's technical documents) so I would totally understand if other MB manufacturers are not gonna integrate this...
I finally got some time to dig into this:
the 'Processor Device Driver' (intelppm.sys, 10.0.10586.0) of Windows 10 (v1511) does have a function called 'IsHwpSupported' which is used to check if HWP is supported by the processor via the CPUID command during the OS boot.
However the driver...
That's because the MSRs are not persistent and reset when the CPU is reset.
While it would be possible for the BIOS to set the MSR for HWP it's the responsibility of the OS to do so. Otherwise an OS not prepared to handle HWP might malfunction or cause all sorts of issues, the BIOS doesn't know...
It never came to my mind to manually mess with the MSRs (at least on a Windows system). But after I read what you did I tried it myself.
So I did set the IA32_PM_ENABLE Bit 0 to 1 and voila, HWP was enabled in my running Windows 10 system. o_O
Tested system: Win 10 Pro 64Bit v1511, i7-6700...
Good questions. Only MS / Intel could actually answer them I guess. Sounds plausible that some other criteria than the CPU itself could influence the HWP status. E.g. sth. like the PreferredPowerManagementProfile entry mentioned by you. Unfortunately you hardly can find any official...
I'm a bit confused how some people here got SST (HWP) enabled in Windows with a BIOS update. As coercitiv already described, HWP usually has to be activated by the OS. And afaik Windows 10 v1511 doesn't support HWP for Desktop Skylakes but only for the Mobile Skylakes.
I've got a ASUS Z170-A...
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