diff --git a/src/cmd/internal/obj/stack.go b/src/cmd/internal/obj/stack.go
index 1a2ee12291..80f6c6c164 100644
--- a/src/cmd/internal/obj/stack.go
+++ b/src/cmd/internal/obj/stack.go
@@ -11,7 +11,7 @@ const (
 	STACKSYSTEM = 0
 	StackSystem = STACKSYSTEM
 	StackBig    = 4096
-	StackGuard  = 1024*stackGuardMultiplier + StackSystem
+	StackGuard  = 720*stackGuardMultiplier + StackSystem
 	StackSmall  = 128
 	StackLimit  = StackGuard - StackSystem - StackSmall
 )
diff --git a/src/runtime/stack.go b/src/runtime/stack.go
index ba1a1bb143..81059965d9 100644
--- a/src/runtime/stack.go
+++ b/src/runtime/stack.go
@@ -90,7 +90,7 @@ const (
 
 	// The stack guard is a pointer this many bytes above the
 	// bottom of the stack.
-	_StackGuard = 1024*sys.StackGuardMultiplier + _StackSystem
+	_StackGuard = 720*sys.StackGuardMultiplier + _StackSystem
 
 	// After a stack split check the SP is allowed to be this
 	// many bytes below the stack guard.  This saves an instruction
diff --git a/test/nosplit.go b/test/nosplit.go
index 2bf7077808..082fc3b0e6 100644
--- a/test/nosplit.go
+++ b/test/nosplit.go
@@ -302,13 +302,13 @@ TestCases:
 				// Instead of rewriting the test cases above, adjust
 				// the first stack frame to use up the extra bytes.
 				if i == 0 {
-					size += (1024 - 128) - 128
+					size += (720 - 128) - 128
 					// Noopt builds have a larger stackguard.
 					// See ../src/cmd/dist/buildruntime.go:stackGuardMultiplier
 					// This increase is included in obj.StackGuard
 					for _, s := range strings.Split(os.Getenv("GO_GCFLAGS"), " ") {
 						if s == "-N" {
-							size += 1024
+							size += 720
 						}
 					}
 				}