I am using this query to find group links and grouping number of votes on them and then sorting it

If i don't put order by, everything is fine....but as soon as i put order by the query becomes slow and my page cannot open

select sum(votes) as votes,url from sortingdisplay where mydate>=DATE_ADD(CURRENT_DATE,INTERVAL -7 DAY) and mydate<=CURRENT_DATE Group by url ORDER BY votes

Is there any alternative to sort rather than order by...because order by is causing all this problem