you can by limiting affinity like others have mentioned (task manager > details tab > finding the exe file > right click > set affinity > removing some cpu ) but the affinity will reset each time you launch the application to permanently limit the affinity for an application you need to create a shortcut with specific command to do that right click (on the desktop or any folder) > New > shortcut and paste this command :
C:\Windows\System32\cmd.exe /c start "NameOfTheapp" /affinity X "path to the app exe"
C:\Windows\System32\cmd.exe /c start "HandBrake" /affinity 3F "G:\Program Files\HandBrake\HandBrake.exe"
X is hexadecimal value so for example if in the affinity tab i have 8 cpu and i want to use the first 6 you need to imagine each cpu as binary 0 is off and 1 is on
so i get 00111111 then you convert this binary to hexadecimal (you can google binary to hex and use calculator) so it's 3F in hex
the shortcut will have the cmd icon to change it to the app icon right click on the shortcut > properties > shortcut tab > change icon > browse to the app exe file and select it and hit ok now you will have the app icon