Sharepoint - Bad SharePoint Performance

Antivirus Always cause the issue. MSFT have the guideling regaring the AV. You ave to exclude the Certain folders from the AV scan.

• Hive Folder
• ULS Logs Folder
• IIS virtual Direcotries
• App / Local Fodler for the service account.
• SharePoint Installed Location and more Please check Below KB for complete list of the exclusion.

Certain folders may have to be excluded from antivirus scanning when you use file-level antivirus software in SharePoint