WP7 browser requirements clearly states that it doesn’t support IE6 for lot of functionalities but recently as part of theme development we had to support the IE6 browser for the portal 7 and IE6 browser is getting freeze very often .
We tried following different steps to make the application works in IE6
1. Make sure no of CSS files less than 31 (Click Here more details).
2. Make sure you don’t have combination of HTTPS , Compression (GIP) & chunked encoding enabled. Click Here for microsoft support article explains about the IE6 freezing.