One UEFI setting that really helped me

[Ferr0]

I want to preface this by saying I don't have hard data proving the claims of my subjective anecdotal experience. I feel like this topic can be prone to derailing into pseudoscience pretty easily but one specific UEFI setting that I feel really affected my input lag was a hidden Speedshift setting. Even if I disabled Intel Speedshift in the normal UEFI this one setting wasn't being disabled and after using GRUB to change the setting my PC felt how I mentally thought it should.

So along with disabling regular Speedshift, C States, Hyperthreading, and RAM PPD in UEFI the last setting I changed that was a hidden setting was:

Power & Performance

Intel(R) Speed Shift Technology Interrupt Control | VarStore: CpuSetup, VarOffset: 0x1E0, Size: 0x1
Disabled: 0x0
Enabled: 0x1 (default)

It's different from the normal Speedshift settings and I disabled it using GRUB. I had all those other options disabled a while before trying to disable the hidden speed shift one and it seemed to make a pretty obvious difference. Obviously check your own motherboard's UEFI for the proper GRUB values if you want to disable it.

Thank you for sharing your find on this forum. I noticed this setting before, but I thought it was disabled in the bios with the same parameter. Unfortunately, I can't change the internal bios parameters via grub on the z790 msi, but as soon as I get this opportunity, I will immediately check it. Have you been looking for any explanation about this setting?

I have found no documentation on the setting but judging by the name I'm assuming its power saving related to CPU interrupts.

Any guide on how to change settings in grub?

https://github.com/BoringBoredom/UEFI-E ... odded-bios

If you haven't disabled things like ram power down mode you should do that too with GRUB since it usually isn't exposed in intel bios's except for newer msi boards.

[St1cky]

I dont have intel speedshift in my bios, does this mean i dont have this technology?

If I remember correctly, on my Asus board sometimes it does not show that option in CPU Configuration Page. I would Assume of the board's overclocking functions that just disables Intel SpeedShift technology and hides it. You can check by saving your current profile, and then loading defaults -> restart -> hop back to Bios and see if the option is available now.

If that's the case, I'd still recommend anyone with a board that behaves that way use GRUB to be sure the option I listed is disabled since my EVGA z590 and a Gigabyte z490 I have both keep the Speedshift Interrupt Control on even with the other stuff off. Worth a try

Yes it's always enabled in the BIOS and from what I've seen always hidden.
(Intel(R) Speed ​​Shift Technology Interrupt Control)

[Espionage724]

It's in my Dell Latitude 5591 BIOS as hidden EFI var too:

Code: Select all

			OneOf Prompt: "Intel(R) Speed Shift Technology Interrupt Control", Help: "Enable/Disable Intel(R) Speed Shift Technology Interrupts", QuestionFlags: 0x10, QuestionId: 0x2A3, VarStoreId: 0x1, VarOffset: 0x769, Flags: 0x10, Size: 8, Min: 0x0, Max: 0x1, Step: 0x0
				OneOfOption Option: "Disabled" Value: 0
				OneOfOption Option: "Enabled" Value: 1, Default, MfgDefault
			End 

I disabled it but don't notice a difference.

Edit: I tried it again on latest 1.38.0 BIOS; nothing notable real-world, but doing a MD5 crypto check was near-instant vs a few seconds after disabling SST interrupts and a few other BIOS settings (I did services and etc too so it's hard to tell what improved anything specifically; I'll narrow it down eventually :p)

[JimCarry]

I want to preface this by saying I don't have hard data proving the claims of my subjective anecdotal experience. I feel like this topic can be prone to derailing into pseudoscience pretty easily but one specific UEFI setting that I feel really affected my input lag was a hidden Speedshift setting. Even if I disabled Intel Speedshift in the normal UEFI this one setting wasn't being disabled and after using GRUB to change the setting my PC felt how I mentally thought it should.

So along with disabling regular Speedshift, C States, Hyperthreading, and RAM PPD in UEFI the last setting I changed that was a hidden setting was:

Power & Performance

Intel(R) Speed Shift Technology Interrupt Control | VarStore: CpuSetup, VarOffset: 0x1E0, Size: 0x1
Disabled: 0x0
Enabled: 0x1 (default)

It's different from the normal Speedshift settings and I disabled it using GRUB. I had all those other options disabled a while before trying to disable the hidden speed shift one and it seemed to make a pretty obvious difference. Obviously check your own motherboard's UEFI for the proper GRUB values if you want to disable it.

Thanks for sharing,you can use scewin and export your bios file, and search in it,and if you find it, you can disable enable only need restart pc, for bencmharks for example,does amd have this stuff ?

[Espionage724]

I believe a related option is something like "Threaded logical interrupt mode"; it can be round robin, hash vector, fixed, any of those with "PAIR", and "No Change" (7 options); it defaults to "PAIR fixed".

I'm thinking it only applies with Hyperthreading enabled, and that "No Change" is best (sounds like BIOS would do low-level IRQ/etc balancing on-top of the OS's scheduling)

This tool boots to unlocked BIOS settings: https://github.com/DavidS95/Smokeless_UMAF (says AMD but UMAF_BETA worked for me i5-8400H on Dell Latitude 5591; the settings are wild :p)