diff --git a/src/com/sheepit/client/os/Windows.java b/src/com/sheepit/client/os/Windows.java
index c1381b5..d5e5b56 100644
--- a/src/com/sheepit/client/os/Windows.java
+++ b/src/com/sheepit/client/os/Windows.java
@@ -139,10 +139,6 @@ public class Windows extends OS {
 		else {
 			wproc.setPriority(WinProcess.PRIORITY_BELOW_NORMAL);
 		}
-		if (env != null) {
-			String cores = env.get("CORES");
-			wproc.setAffinity(Integer.parseInt(cores));
-		}
 		return p;
 	}
 	
diff --git a/src/com/sheepit/client/os/windows/Kernel32Lib.java b/src/com/sheepit/client/os/windows/Kernel32Lib.java
index cb0c857..51a30d4 100644
--- a/src/com/sheepit/client/os/windows/Kernel32Lib.java
+++ b/src/com/sheepit/client/os/windows/Kernel32Lib.java
@@ -21,7 +21,6 @@ import com.sun.jna.Library;
 import com.sun.jna.Pointer;
 import com.sun.jna.Structure;
 import com.sun.jna.platform.win32.BaseTSD;
-import com.sun.jna.platform.win32.BaseTSD.DWORD_PTR;
 import com.sun.jna.platform.win32.WinDef;
 import com.sun.jna.platform.win32.WinDef.DWORD;
 import com.sun.jna.platform.win32.WinNT;
@@ -212,13 +211,4 @@ public interface Kernel32Lib extends Library {
 	 */
 	public int SetErrorMode(DWORD uMode);
 	
-	/**
-	 * See : https://msdn.microsoft.com/en-us/library/windows/desktop/ms686247%28v=vs.85%29.aspx
-	 * 
-	 * @param hThread
-	 * @param dwThreadAffinityMask
-	 * @return If the function succeeds, the return value is the thread's previous affinity mask.
-	 */
-	public boolean SetProcessAffinityMask(HANDLE hProcess, DWORD_PTR dwProcessAffinityMask);
-	
 }
diff --git a/src/com/sheepit/client/os/windows/WinProcess.java b/src/com/sheepit/client/os/windows/WinProcess.java
index f64b69b..1bb976d 100644
--- a/src/com/sheepit/client/os/windows/WinProcess.java
+++ b/src/com/sheepit/client/os/windows/WinProcess.java
@@ -26,7 +26,6 @@ import java.util.List;
 
 import com.sun.jna.Native;
 import com.sun.jna.Pointer;
-import com.sun.jna.platform.win32.BaseTSD.DWORD_PTR;
 import com.sun.jna.platform.win32.Kernel32;
 import com.sun.jna.platform.win32.Kernel32Util;
 import com.sun.jna.platform.win32.WinDef.DWORD;
@@ -122,20 +121,6 @@ public class WinProcess {
 		return this.kernel32lib.SetPriorityClass(this.handle, priority);
 	}
 	
-	public boolean setAffinity(int numberCores) {
-		// affects the process to a specific core/cpu, it will reduce the number of switch between core
-		// that way the machine will look "less busy" since default behavior for windows is to put 4 cores 
-		// at 25% instead of 1 core at 100% but from the user point of view, it introduce lag.
-		if (numberCores > 0) {
-			long coreAffinity = 0;
-			for (int i = 0; i < numberCores; i++) {
-				coreAffinity |= 1L << i;
-			}
-			return this.kernel32lib.SetProcessAffinityMask(this.handle, new DWORD_PTR(coreAffinity));
-		}
-		return false;
-	}
-	
 	private void terminate() {
 		Kernel32.INSTANCE.TerminateProcess(this.handle, 0);
 		Kernel32.INSTANCE.CloseHandle(this.handle); // we are sure that the parent Process object is dead