temps are all about delta's not total values unless your looking to know the maximum safe temp for a card. so if your getting 22c outside the case what the temp inside the case out of case temperature is only really relevant to your temps inside the case which is then in turn relevant to the temp of your components.
for example, my ambient temp is currently 23c my in case temp is 27c and my gpu idle is at 34c
however if hypothetically case temp was 40c and my gpu was at 47C then my gpu is doing exactly as good a job keeping itself cool its still only 7c higher than the minium it can possibly be so there is no point in looking at it and trying to take it apart reapply thermal past etc, instead i should be looking at my case and wondering how many places i can cut holes in it and how many fans i can slot in before it sounds like a jet engine taking off
as my case is giving a delta of 17c which is horribly huge.
if your running crossfire in a bad airflow case your cards are going to get toasty toasty warm thats not a problem with the card its a problem with the case that said 82C for a single card on high is pretty bad if i remember rightly when i was running stock cooling on my 5870's on 100% fan speed I usually had a delta of around 45-50c with a case temp of 30ish