Upgrade suspension on hard tail MTB
XCM is an entry level fork - typically found of bikes at the low end of the price range. Its not hard to imagine you have out grown the fork and it is limiting your enjoyment and performance while riding. 

The only way to tell if a better fork is needed, (or is that wanted?) is to take a bike with a better fork for a ride. The main consideration is how much money are you prepared to spend. However, if you take a bike out with a better fork, it will almost certainly be a better bike in every other way as well - so be careful of the comparison - you could esily set yourself up to be disappointed. 

To make a measurable difference, you would need to install a fork that was of far better quality than the rest of the bike, and much of shocks improvement (hence the money) would be wasted by the bike. 

It is rare that a fork upgrade (as opposed to a replacement of a faulty fork) makes sense - the manufacturers build a bike to a cost and the quaility/performance of components match. Forks are very expensive - probably more than the bike is worth. 80mm travel is not enough for serious trail riding - you might push out to 100mm without upsetting geometry too much, but that is still low by today standards. 

Upgrading the whole bike is a much better idea. Put the money you get from selling the bike and the amount a fork would cost into a new (or even better - used) bike.