diff --git a/README.md b/README.md
index c446450..5b72d8c 100644
--- a/README.md
+++ b/README.md
@@ -25,14 +25,22 @@ LPCNet at 1733 bits/s using direct-split quantiser:
 ```
 sox ../../wav/wia.wav -t raw -r 16000 - | ./lpcnet_enc -s | ./lpcnet_dec -s | aplay -f S16_LE -r 16000
 ```
-# CTests
+
+## Manually Selecting SIMD Technology
+
+Cmake will select the fastest SIMD available (AVX/SSSE/None), however you can manually select e.g.:
+```
+make -DDISABLE_CPU_OPTIMIZATION=ON -DSSE=ON -DCODEC2_BUILD_DIR=~/codec2/build_linux ..
+```
+
+## CTests
 
 ```
 $ cd ~/LPCNet/build_linux
 $ ctest
 ```
 
-Note, due to precision/library issues several tests (1-3) will only pass on certain machines such as Ubuntu 16 and 18, Ubuntu 17 is known to fail.
+Note, due to precision/library issues several tests (1-3) will [only pass on some machines](https://github.com/drowe67/LPCNet/issues/17).
 
 # Reading Further