Update README.md

Author: andrinr

README.md

@@ -44,7 +44,7 @@ When measuring the execution time of the power spectrum calculation, cosmax is f
 <img src="https://raw.githubusercontent.com/andrinr/cosmax/refs/heads/main/data/benchmark.png" alt="drawing" width="300"/>
 
 This is suprising, since PowerBox is based on FFTW, a highly optimized C library for Fourier Transforms. We have excluded the warmup execution time of the JAX JIT compiler, which includes optimization and compilation of the function. For this reason, you might not see a speedup but a slowdown if powerbox is replaced with cosmax naively.
-Generally speaking, the performance gains of cosmax are felt, when the power spectrum calculations are done **repeatedly**, e.g. in optimization loops.
+Generally speaking, the performance gains of cosmax are felt, when the power spectrum calculations are done **repeatedly**, e.g. in optimization loops. Note that this performance improvmenet does not originate from any smart performance increasing tricks used in cosmax, but rather the power of XLA and JAX. 
 
 ## Limitations