diff --git a/Classes/Stubbing/KWIntercept.m b/Classes/Stubbing/KWIntercept.m
index b1a46ffe..79107895 100644
--- a/Classes/Stubbing/KWIntercept.m
+++ b/Classes/Stubbing/KWIntercept.m
@@ -62,6 +62,8 @@ IMP KWForwardingImplementationForMethodEncoding(const char* encoding) {
     const NSUInteger stretLengthThreshold = 4;
 #elif TARGET_CPU_X86
     const NSUInteger stretLengthThreshold = 8;
+#elif TARGET_CPU_X86_64
+    const NSUInteger stretLengthThreshold = 16;
 #else
     // TODO: This just makes an assumption right now. Expand to support all
     // official architectures correctly.