Hello frns, Hope y'all r doing gud.
If you're encountering EAC-3 problems then u are at the right place!
The reason of making another topic is because i encountered this problem after upgrading from windows 7 to windows 10.
1-Disabling V-Sync, if you're using 60Hz monitor and can't play without having V-Sync turned on (like me) then do the following: Disable V-Sync and close the game using the 'X' Button not from the task manager to save the settings for the next run. After you start S4 and ready to play make sure to enable V-Sync again. To not mess with the settings again close S4 from task manger under 'Details' not "Processes" tab (Force closing) Your previous saved settings wont be changed.
2-Close unnecessary programs and services: Open your task manager and click on 'Startup' tab then disable the programs that you don't want to run for a faster boot time and to prevent EAC-3 error. As for services hold Windows Key + R and type 'msconfig' or search for 'System Configuration' in the start menu then click on 'Services' tab and then tick on 'Hide all Microsoft services' and disable the unnecessary services.
3-Increase your Random Access Memory (RAM) if you're still using 2 gigs of RAM upgrade it to 4 at least
4-Use SSD: If you have SSD installed in ur machine move S4 league to it, put all apps/games on ssd, and use hdd for media.
5-Increase Virtual Memory: this one worked for me after upgrading to win 10. Search for 'Advanced System Settings' in start menu and under 'Performance' click on 'Settings' and click on 'Advanced' tab you should see 'Virtual Memory' click on 'Change' and do the following, unselect 'Automatically manage paging file size for all drives' then select 'Custom size'. In initial size write the amount of installed RAM in MBs for example if you have 16GB of RAM (16GBx1024MB=16384MB) that's for the initial size. For the Maximum size it should be times 1.5 or 2 *up to you* for me i use this.z Hit 'Set' then 'OK' and restart your computer.
6-Disabling Superfetch/SysMain service: they are the same just different name on the latest build of win10, description 'Maintains and improves system performance over time.' Disabling it prevented high Disk usage. how to disable it? Open Services and search for Superfetch or SysMain and Disable it.
7-If you're using old toaster: Disable windows visual effects. how to? Same as step n.5 but 'Visual Effects' tab instead of 'Advanced' Select 'Adjust for best performance'
8-Disable fullscreen optimizations: you can read about it here and to disable it for S4 League. Right click on patcher_s4 and In the context menu, select Properties. Go to the Compatibility tab. Enable the option Disable fullscreen optimizations.
9-Repair EAC Service, Open S4 folder and look for EasyAntiCheat folder then open EasyAntiCheat_Setup and click on 'Repair Service' or uninstall then install it again.
10-Reinstall the game. (if nothing worked)
Don't use external softwares to Boost your PC if you can do it's job without impacting memory usage.