diff --git a/source/blender/blenkernel/intern/fcurve.c b/source/blender/blenkernel/intern/fcurve.c
index 67bee90e91c..e86cfce6fd9 100644
--- a/source/blender/blenkernel/intern/fcurve.c
+++ b/source/blender/blenkernel/intern/fcurve.c
@@ -1097,6 +1097,12 @@ void driver_free_variable (ChannelDriver *driver, DriverVar *dvar)
 		BLI_freelinkN(&driver->variables, dvar);
 	else
 		MEM_freeN(dvar);
+
+#ifndef DISABLE_PYTHON
+	/* since driver variables are cached, the expression needs re-compiling too */
+	if(driver->type==DRIVER_TYPE_PYTHON)
+		driver->flag |= DRIVER_FLAG_RENAMEVAR;
+#endif
 }
 
 /* Change the type of driver variable */
@@ -1149,6 +1155,12 @@ DriverVar *driver_add_new_variable (ChannelDriver *driver)
 	/* set the default type to 'single prop' */
 	driver_change_variable_type(dvar, DVAR_TYPE_SINGLE_PROP);
 	
+#ifndef DISABLE_PYTHON
+	/* since driver variables are cached, the expression needs re-compiling too */
+	if(driver->type==DRIVER_TYPE_PYTHON)
+		driver->flag |= DRIVER_FLAG_RENAMEVAR;
+#endif
+
 	/* return the target */
 	return dvar;
 }
diff --git a/source/blender/makesdna/DNA_anim_types.h b/source/blender/makesdna/DNA_anim_types.h
index 5b0dfbdd574..958add428a4 100644
--- a/source/blender/makesdna/DNA_anim_types.h
+++ b/source/blender/makesdna/DNA_anim_types.h
@@ -371,7 +371,9 @@ typedef enum eDriver_Flags {
 		// TODO: this needs to be implemented at some stage or left out...
 	//DRIVER_FLAG_LAYERING	= (1<<2),
 		/* use when the expression needs to be recompiled */
-	DRIVER_FLAG_RECOMPILE	= (1<<3), 
+	DRIVER_FLAG_RECOMPILE	= (1<<3),
+		/* the names are cached so they dont need have python unicode versions created each time */
+	DRIVER_FLAG_RENAMEVAR	= (1<<4),
 } eDriver_Flags;
 
 /* F-Curves -------------------------------------- */
diff --git a/source/blender/makesrna/intern/rna_fcurve.c b/source/blender/makesrna/intern/rna_fcurve.c
index 1fa731f512b..b6b05eb4896 100644
--- a/source/blender/makesrna/intern/rna_fcurve.c
+++ b/source/blender/makesrna/intern/rna_fcurve.c
@@ -129,6 +129,15 @@ static void rna_DriverTarget_update_data(Main *bmain, Scene *scene, PointerRNA *
 	}
 }
 
+static void rna_DriverTarget_update_name(Main *bmain, Scene *scene, PointerRNA *ptr)
+{
+	ChannelDriver *driver= ptr->data;
+	rna_DriverTarget_update_data(bmain, scene, ptr);
+
+	driver->flag |= DRIVER_FLAG_RENAMEVAR;
+
+}
+
 /* ----------- */
 
 static StructRNA *rna_DriverTarget_id_typef(PointerRNA *ptr)
@@ -764,7 +773,7 @@ static void rna_def_drivervar(BlenderRNA *brna)
 	prop= RNA_def_property(srna, "name", PROP_STRING, PROP_NONE);
 	RNA_def_struct_name_property(srna, prop);
 	RNA_def_property_ui_text(prop, "Name", "Name to use in scripted expressions/functions. (No spaces or dots are allowed. Also, must not start with a symbol or digit)");
-	RNA_def_property_update(prop, 0, "rna_DriverTarget_update_data"); // XXX
+	RNA_def_property_update(prop, 0, "rna_DriverTarget_update_name"); // XXX
 	
 	/* Enums */
 	prop= RNA_def_property(srna, "type", PROP_ENUM, PROP_NONE);
diff --git a/source/blender/python/intern/bpy_driver.c b/source/blender/python/intern/bpy_driver.c
index 6f2f7a6f3b3..f80d79d9a2a 100644
--- a/source/blender/python/intern/bpy_driver.c
+++ b/source/blender/python/intern/bpy_driver.c
@@ -177,14 +177,29 @@ float BPY_pydriver_eval (ChannelDriver *driver)
 		}
 	}
 
+	if(driver->expr_comp==NULL)
+		driver->flag |= DRIVER_FLAG_RECOMPILE;
+
 	/* compile the expression first if it hasn't been compiled or needs to be rebuilt */
-	if((driver->flag & DRIVER_FLAG_RECOMPILE) || (driver->expr_comp==NULL)) {
+	if(driver->flag & DRIVER_FLAG_RECOMPILE) {
 		Py_XDECREF(driver->expr_comp);
 		driver->expr_comp= PyTuple_New(2);
 
 		expr_code= Py_CompileString(expr, "<bpy driver>", Py_eval_input);
 		PyTuple_SET_ITEM(((PyObject *)driver->expr_comp), 0, expr_code);
 
+		driver->flag &= ~DRIVER_FLAG_RECOMPILE;
+		driver->flag |= DRIVER_FLAG_RENAMEVAR; /* maybe this can be removed but for now best keep until were sure */
+	}
+	else {
+		expr_code= PyTuple_GET_ITEM(((PyObject *)driver->expr_comp), 0);
+	}
+
+	if(driver->flag & DRIVER_FLAG_RENAMEVAR) {
+		/* may not be set */
+		expr_vars= PyTuple_GET_ITEM(((PyObject *)driver->expr_comp), 1);
+		Py_XDECREF(expr_vars);
+
 		/* intern the arg names so creating the namespace for every run is faster */
 		expr_vars= PyTuple_New(BLI_countlist(&driver->variables));
 		PyTuple_SET_ITEM(((PyObject *)driver->expr_comp), 1, expr_vars);
@@ -192,11 +207,8 @@ float BPY_pydriver_eval (ChannelDriver *driver)
 		for (dvar= driver->variables.first, i=0; dvar; dvar= dvar->next) {
 			PyTuple_SET_ITEM(expr_vars, i++, PyUnicode_InternFromString(dvar->name));
 		}
-
-		driver->flag &= ~DRIVER_FLAG_RECOMPILE;
 	}
 	else {
-		expr_code= PyTuple_GET_ITEM(((PyObject *)driver->expr_comp), 0);
 		expr_vars= PyTuple_GET_ITEM(((PyObject *)driver->expr_comp), 1);
 	}