Hellbovine

Well-Known Member
The Spectre and Meltdown vulnerabilities were patched in the year 2019, but the issue is that Microsoft fixed it with a solution that decreases performance. Intel and AMD worked on microcode updates, and fixed these problems in future processors too, but users of older hardware may want to disable these patches to reclaim performance, which Microsoft acknowledges in support articles (link).

DISABLE SPECTRE AND MELTDOWN
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\Memory Management]
"FeatureSettingsOverrideMask"=dword:00000003
"FeatureSettingsOverride"=dword:00000003

ADDITIONAL INFORMATION
Download InSpectre by Gibson Research Corporation, or use the powershell method mentioned later in the thread to see what settings the computer is currently using. It should be noted that these tweaks will reduce the security of Windows to gain some performance, and that may not be the best situation for all users. Gamers on old hardware may find these tweaks useful, but using newer hardware would make this tweak unnecessary.
 
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Also, standard disclaimer here about security issues by disabling it. Don't mess with this if you don't know what you are doing or if you don't have safe internet habits. You can enable protections again using these tools, and you can test this while offline for extra safety.
 
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Also, disclaimer here about security issues by disabling, blah blah blah. Don't mess with it if you don't know what you are doing or if you don't have safe internet habits.

You can immediately enable the protections again using the InSpectre tool as well, fyi.
Hello. On my old AMD processor, both options are not active.
 

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That's odd, and exactly why I wanted to test it because the articles are complex. So in your case the options are not only grayed out, but Spectre is disabled, and Meltdown is enabled. I'm not quite sure what to make of that. Are there any other AMD users that can test this? Also, did you run InSpectre in admin mode, maybe that's what caused this?
 
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Oh, did you run InSpectre in admin mode? Maybe that's why it's greyed out.
Yes of course in administrator mode. I downloaded the program from the official site, the latest version. The program shows that there are no performance problems. If you believe the test program, then not all AMD processors need a fix.
 
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You'll have to please help me on how to install the SpeculationControl since I'm unfamiliar with PowerShell. My PC is offline at the moment, so if I download the file using the manual link how do I install it and then run it?
 
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Speculation control settings for PSDP [primary stale data propagator]

Windows OS support for PSDP mitigation is present: True
Hardware is vulnerable to PSDP: False


BTIHardwarePresent : True
BTIWindowsSupportPresent : True
BTIWindowsSupportEnabled : True
BTIDisabledBySystemPolicy : False
BTIDisabledByNoHardwareSupport : False
BTIKernelRetpolineEnabled : True
BTIKernelImportOptimizationEnabled : True
RdclHardwareProtectedReported : True
RdclHardwareProtected : False
KVAShadowRequired : False
KVAShadowWindowsSupportPresent : True
KVAShadowWindowsSupportEnabled : False
KVAShadowPcidEnabled : False
SSBDWindowsSupportPresent : True
SSBDHardwareVulnerable : True
SSBDHardwarePresent : True
SSBDWindowsSupportEnabledSystemWide : False
L1TFHardwareVulnerable : False
L1TFWindowsSupportPresent : True
L1TFWindowsSupportEnabled : False
L1TFInvalidPteBit : 0
L1DFlushSupported : False
HvL1tfStatusAvailable : False
HvL1tfProcessorNotAffected : False
MDSWindowsSupportPresent : True
MDSHardwareVulnerable : False
MDSWindowsSupportEnabled : False
FBClearWindowsSupportPresent : True
SBDRSSDPHardwareVulnerable : False
FBSDPHardwareVulnerable : False
PSDPHardwareVulnerable : False
FBClearWindowsSupportEnabled : False



Execution Policy Change
Execution policy helps protect against untrusted scripts. Changing the execution policy can
imply exposure to the security risks described in the about_Execution_Policies help topic at
https://go.microsoft.com/fwlink/?LinkID=135170. Do you want to change the execution policy?
[Y] Yes [A] Yes to All [N] No [T] No to All Suspend [?] Help (default is "N"):


I followed the first method in the link, now what?
 
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These Microsoft documents and powershell output are difficult and uncoordinated, they could be written in a more succint and organized manner. I haven't used the powershell method myself yet, but after briefly reading through the documents I think I can help with it.

1) Read this paper (link) and notice towards the top it says CVE-2017-5715 (branch target injection). Microsoft is assuming we know what that means, but they don't have a humanized name next to it, so it's easy to not know that CVE-2017-5715 is the assigned number for one of the "Spectre" mitigations and is how Microsoft keeps track of these things.

2) Now that we know what to look for, in that same link from above use ctrl+f and search for 5715 and you'll find another place where it's mentioned, with related lines of output below it. The first one says, "Hardware support for branch target injection mitigation is present" and can be True or False. This is confusing too, because the powershell output doesn't match that text. We must then assume, "BTIHardwarePresent" probably means "BTI" is an abbreviation for "Branch Target Injection" and is what we are looking for.

Long story short, I think you are looking for these lines in the powershell output.
Spectre Disabled = BTIWindowsSupportEnabled : False
Meltdown Disabled = RdclHardwareProtected : False

Essentially, just install the registry keys from the main post, then reboot and see how the powershell output changed to confirm this theory. You could also run the InSpectre tool to get a visual output that literally says if Spectre and Meltdown are enabled or not.
 
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These Microsoft documents and powershell output are difficult and uncoordinated, they could be written in a more succint and organized manner. I haven't used the powershell method myself yet, but after briefly reading through the documents I think I can help with it.

1) Read this paper (link) and notice towards the top it says CVE-2017-5715 (branch target injection). Microsoft is assuming we know what that means, but they don't have a humanized name next to it, so it's easy to not know that CVE-2017-5715 is the assigned number for one of the "Spectre" mitigations and is how Microsoft keeps track of these things.

2) Now that we know what to look for, in that same link from above use ctrl+f and search for 5715 and you'll find another place where it's mentioned, with related lines of output below it. The first one says, "Hardware support for branch target injection mitigation is present" and can be True or False. This is confusing too, because the powershell output posted in this thread doesn't match that text. We must then assume, "BTIHardwarePresent" probably means "BTI" is an abbreviation for "Branch Target Injection" and is what we are looking for.

Long story short, I think you are looking for these lines in the powershell output.
Spectre Disabled = BTIWindowsSupportEnabled : False
Meltdown Disabled = RdclHardwareProtected : False

Essentially, just install the registry keys from the main post, then reboot and see how the powershell output changed to confirm this theory. You could also run the Gibson tool to get a visual output that literally says if Spectre and Meltdown are enabled or not.

In my case it is an AMD Ryzen, can these registry lines work? Well, I'll test it here. Do any of these topic changes change the hardware level?
 
I'm not sure what you mean about the hardware level. I would think of this registry tweak as being identical to a pretend scenario where Microsoft puts "Enable Spectre mitigations" and "Enable Meltdown mitigations" inside the Security Center app, and has a toggle for "On" or "Off" that modifies the registry keys from the first post. That's how most tweaks we use on this forum work, they just don't always have an interface to click on.
 
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Hi, i think most people on the internet don't know how these protections work and how to kill them as they make NO(!) sense on a consumer, workstation or server system.
There are three ways your system handles mitigations:
1. Microcode Update via BIOS/UEFI update
2. Microcode Update via software (C:\Windows\System32\mcupdate_GenuineIntel.dll)
3. Software based mitigations

So even if you have set the correct registry keys to disable the mitigations they will get applied.
 
...even if you have set the correct registry keys to disable the mitigations they will get applied.
Do you have some screenshots to post which verify this? If it's true, benchmarking with registry mitigations enabled/disabled will show no difference or a slight one, while reverting/deleting microcode will show additional changes. I've heard about the suggestion of deleting microcode before, but I've also never seen any evidence as to why.

On that note, how are people confident that the performance they are seeing from reverting/deleting microcode is only related to Spectre/Meltdown and isn't actually coming from the other mitigations and fixes included in the updates? Users need to consider what else they are losing by doing that, as there are other security mitigations not discussed here, and it could revert beneficial fixes too.
 
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Users who are most interested in defeating mitigation are typically running older HW which is greatly impacted. Some of them don't have BIOS updates (like my PC is too old), so all mitigations are done thru Windows. Obviously there are no guarantees, we're just presenting what needs to be done to disable the default Windows behavior (reg fixes and removing microcode DLL's).
 
Online Everyday PC - Enabled.
Online Gamer PC - FaFo(MaFo).
Offline Workstation/Offline Specialised PC - Enabled or Disabled to suit your needs/whim.
Guarantee most people wont notice a difference enabled or not.

If like me you prefer a single master gold image that you customise later as per the requirements then keep them in the image and Disable if needed,
 
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