I'm specifically basing this list off of 8.1, but I figure it will mostly apply to 8.0 as well due to 8.1 basically being a renamed service pack.
This post will go over tasks in Windows 8.1 that you can disable or delete for more performance, privacy, and security. This list is based off of the upcoming Windows 8.1 Updated v2. (Link here when finished)
I have been able to create a batch file that disables and delete these tasks, it is attached to the post. Not all tasks in the list are deleted due to some of them potentially being useful. Here's what isn't touched below.
► Show Spoiler
Not touched:
AppID - VerifiedPublisherCertStoreCheck
Blackbird recommends disabling, but it seems to already be disabled. Sounds like it would be pretty important for security but idk.
DiskDiagnostic - Microsoft-Windows-DiskDiagnosticResolver
Blackbird recommends disabling, but it seems to already be disabled. Sounds like it would be pretty important notifying the user if their hard drive is about to fail but idk.
FileHistory - File History (maintenance mode)
This seems to be telemetry, but I'm not too sure since it could just be periodic backups. Maybe disable just in case?
Time Synchronization - ForceSynchronizeTime & SynchronizeTime
Optional, you might want this if you care about accurate time and don't block the NTP port (123).
User Profile Service - HiveUploadTask
Blackbird recommends disabling, but it seems to already be disabled. May be useful if you use roaming profiles.
Windows Defender - Windows Defender Scheduled Scan
Blackbird recommends disabling, but may be useful if you wish to use Windows Defender.
Disabled but not deleted:
Diagnosis - Scheduled
This seems to be telemetry, but I'm not too sure since it could just be periodic maintenance. Maybe disable just in case?
Power Efficiency Diagnostics - AnalyzeSystem
This seems to be telemetry, but I'm not too sure since it could help with power consumption. Maybe disable just in case?
Main list if you prefer to do it manually:
► Show Spoiler
To open Task Scheduler, press the windows key, type taskschd.msc, and press enter. Go under Microsoft > Windows and delete these tasks:
AppID - SmartScreenSpecific
Useless at best, telemetry at worst.
AppID - VerifiedPublisherCertStoreCheck
Blackbird recommends disabling, but it seems to already be disabled. Sounds like it would be pretty important for security but idk.
Application Experience - All
Telemetry.
Autochk - All
Telemetry.
Customer Experience Improvement Program - All
Telemetry.
Device Setup - Metadata Refresh
Useless at best, telemetry at worst.
Diagnosis - Scheduled
This seems to be telemetry, but I'm not too sure since it could just be periodic maintenance. Maybe disable just in case?
DiskDiagnostic - Microsoft-Windows-DiskDiagnosticDataCollector
Telemetry.
DiskDiagnostic - Microsoft-Windows-DiskDiagnosticResolver
Blackbird recommends disabling, but it seems to already be disabled. Sounds like it would be pretty important notifying the user if their hard drive is about to fail but idk.
DiskFootprint - Diagnostics
Telemetry.
FileHistory - File History (maintenance mode)
This seems to be telemetry, but I'm not too sure since it could just be periodic backups. Maybe disable just in case?
IME - SQM data sender
Telemetry.
Location - Notifications
Location tracking.
Maintenance - WinSAT
Annoying and useless. Can just randomly start in the background and cause issues with applications (especially games) if you happen to be using them at the time it runs.
Mobile Broadband Accounts - MNO Metadata Parser
Useless at best, telemetry at worst.
NetTrace - GatherNetworkInfo
Telemetry.
PerfTrack - BackgroundConfigSurveyor
Telemetry.
PI - Sqm-Tasks
Telemetry.
Power Efficiency Diagnostics - AnalyzeSystem
This seems to be telemetry, but I'm not too sure since it could help with power consumption. Maybe disable just in case?
RemoteAssistance - RemoteAssistanceTask
It looks useless and Blackbird recommends disabling it.
SettingSync - BackgroundUploadTask, BackupTask, and NetworkStateChangeTask
Useless at best, telemetry at worst.
Setup - EOSNotify & EOSNotify2
Windows 8.1 end of support nagging.
Shell - CreateObjectTask, FamilySafetyMonitor, FamilySafetyRefresh, and FamilySafetyUpload
Useless at best, telemetry at worst.
Time Synchronization - ForceSynchronizeTime & SynchronizeTime
Optional, you might want this if you care about accurate time and don't block the NTP port (123).
User Profile Service - HiveUploadTask
Blackbird recommends disabling, but it seems to already be disabled. May be useful if you use roaming profiles.
UPnP - UPnPHostConfig
Seems to be for enabling the UPnP service if the user disables it, doesn't need to run even if you don't disable it.
Windows Defender - Windows Defender Scheduled Scan
Blackbird recommends disabling, but may be useful if you wish to use Windows Defender.
Windows Error Reporting - QueueReporting
Telemetry.