CSGOTWEAKS

Go to Start - Computer - Properties - Advanced system settings - Advanced - Performance - Settings - Custom - Disabling it all gives the best performance.

Enormous input lag. Here is reg file that permanently disables it.

Typically, a lot of unnecessary services are working in Windows by default, so disable all of them (if possible). The link below is a registry file for disabling some services.

Small programm with different presets (safe, extreme etc). Choose extreme at bottom, then service - check all - File - Apply services (orCtrl+S), reboot.

By default there are plenty tasks in Windows 10 in the task manager, that send data about operation of the system, many Metro applications (I haven't started them since start of Windows 10) and other garbage. Fortunately, craftsman created DWS (Destroy Windows Spying). Set the settings as in the screenshot. ATTENTION!: Do not tick "Add spyware domains to hosts" - Skype will stop working :).

Without going into too much detail, Blackbird employs some known and less-known techniques to fully disarm Windows while leaving the smallest possible footprint.

Press WIN+R, type msconfig.exe, go to the "Services", tick "Hide all Microsoft Services", remove the tick from everything we don't use, except anti-cheats, etc.

Set your bitrate to 16bit 44.1k, anything higher can cause a delay. Go to start - control panel - sound - choose ur device - properties - advanced. Same with Recording devices. Disable crystallizer, eax and other things.

Right mouse button on PC - Device manager - sound video and game controllers - Nvidia High Definition Audio - right mouse button - disable. U can disable all unwanted devices, but u do it at ur own risk.

to NVIDIA Control Panel - Manage 3D Settings.
Maximum pre-rendered frames - Set to 1
Power management mode - Set to Prefer maximum performance
Texture filtering - Quality - Set to High performance
Vertical sync - Set to Off
Shader cache - Set to Off
Multidisplay - Set to Single display performance
Virtual Reality pre-rendered frames - Set to 1
What AMD users shall do? Look for the same settings in you Control Center, change them in the same way, maybe later I will add screenshots with the AMD drivers setup.

Go to Start - Control Panel - Hardware and Sounds - Power Options - Set to High Performance.

this command turns on/off HPET (High Precision Event Timer) at the Windows level, you can achieve interesting results in combination with turning on/off this option in the BIOS. For enabling HPET in Windows press WIN+R, type cmd.exe, run as administrator, then type "bcdedit /set useplatformclock true"
Reboot. To turn it OFF type:
"bcdedit /deletevalue useplatformclock"

This one is hugely noticeable. Go to the start menu, in the search box type "Windows Defender" and open it. Go to Tools/Options, then go to the last tab at the bottom and uncheck the box labeled "Use this Program". Or u can use services.msc and find it here, WIN+R on desktop, type services.msc, find windows defender and disable it. U can remove it from autostart in Ccleaner.

Relevant for windows 7 (on win10 disabled by default). Download CPU Core Parking manager, raising the slider to 100%, Apply, reboot.