diff --git a/timm/models/layers/activations.py b/timm/models/layers/activations.py
index 165b7951..6f8d2f89 100644
--- a/timm/models/layers/activations.py
+++ b/timm/models/layers/activations.py
@@ -12,7 +12,7 @@ from torch import nn as nn
 from torch.nn import functional as F
 
 
-_USE_MEM_EFFICIENT_ISH = False
+_USE_MEM_EFFICIENT_ISH = True
 if _USE_MEM_EFFICIENT_ISH:
     # This version reduces memory overhead of Swish during training by
     # recomputing torch.sigmoid(x) in backward instead of saving it.