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@@ -129,7 +129,7 @@ NNoM now use the local pure C backend implementation by default. Thus, there is
 
 
 ## Optimization
-You can select [CMSIS-NN/DSP](https://github.com/ARM-software/CMSIS_5/tree/develop/CMSIS/NN) as the backend for about 5x performance with ARM-Cortex-M4/7/33/35P. 
+[CMSIS-NN/DSP](https://github.com/ARM-software/CMSIS_5/tree/develop/CMSIS/NN) is an optimized backend for ARM-Cortex-M4/7/33/35P. You can select it for up to 5x performance compared to the default C backend. NNoM will use the equivalent method in CMSIS-NN if the condition met. 
 
 Check [Porting and optimising Guide](docs/Porting_and_Optimisation_Guide.md) for detail.