diff --git a/README.md b/README.md
index 5a54e9662c..be900411d6 100644
--- a/README.md
+++ b/README.md
@@ -41,8 +41,9 @@ cd opendbc
 ./test.sh # all-in-one dependency installation, compiling, linting, and tests. It's what runs in CI
 ```
 
-[`examples/`](examples/) contains small example programs that can read state from the car and control the steering, gas, and brakes.
-[`examples/joystick.py`](examples/joystick.py) allows you to control a car with a joystick.
+* [`examples/`](examples/) contains small example programs that can read state from the car and control the steering, gas, and brakes.
+* [`examples/joystick.py`](examples/joystick.py) allows you to control a car with a joystick.
+* running with `FAST=1` results in snappier build times (ie. `FAST=1 ./test.sh`)
 
 ### Project Structure
 * [`opendbc/dbc/`](opendbc/dbc/) is a repository of [DBC](https://en.wikipedia.org/wiki/CAN_bus#DBC) files
diff --git a/SConstruct b/SConstruct
index e3e2e64cbc..abfea153fc 100644
--- a/SConstruct
+++ b/SConstruct
@@ -37,7 +37,7 @@ env = Environment(
   CCFLAGS=[
     "-g",
     "-fPIC",
-    "-O0",
+    "-O0" if os.environ.get("FAST") else "-O2",
     "-Wunused",
     "-Werror",
     "-Wshadow",