diff --git a/README.md b/README.md
index b1a58a8f..b57bfcf9 100644
--- a/README.md
+++ b/README.md
@@ -78,7 +78,7 @@ optim.step()
 
 ### GPU Support?!
 
-tinygrad supports GPUs through PyOpenCL. Not all ops are supported yet.
+tinygrad supports GPUs through PyOpenCL. Not all ops are supported yet on the backward pass.
 
 ```python
 from tinygrad.tensor import Tensor
@@ -93,6 +93,8 @@ Despite being tiny, tinygrad supports the full EfficientNet. Pass in a picture t
 python3 examples/efficientnet.py https://upload.wikimedia.org/wikipedia/commons/4/41/Chicken.jpg
 ```
 
+protip: Set "GPU=1" environment variable if you want this to go faster.
+
 ### The promise of small
 
 tinygrad will always be below 1000 lines. If it isn't, we will revert commits until tinygrad becomes smaller.