No you are right - windows is the correct speed, mac is slow. What are your mac specs?
Can you try one thing?
1) Right click on the app, select "show package contents"
2) Navigate to Contents/Resources/assets/data/config.xml
3) Find the second line of actual code:
<display width="1280" height="720" fullscreen="false" legacyShader="false" />
Change legacyShader="false" to legacyShader="true"
(be careful with this file, one typo and game CRASH)
Then save the file, close it, and launch the game again. Let us know how it goes?