Hi seignthelas,
It, most unfortunately, seems that a combination of horrible R:TW and M2:TW memory leak bugs and having a large number of memory theiving programs running in the background, is resulting in a large slow down in performance. To enhance your PC, hopefully removing the horrible memory thieving background processes that are resulting in the slow down, simply follow this guide. Hope this helps, cheers!

BTW, the guide is currently unavailable - the site seems to be enduring a downtime, my sincere apologies.