Can't add much most any distro will run on 8 GB ram no problem. For gaming the Graphics card support maybe as important. KDE is a good choice it's not that hard on hardware as it used to be and is comparable to say XFCE now. But Just try the ones your interested in on live usb/DVD and see if it meets your needs and your system resources. Some distros will automatically install Nvidia drivers for instance others do not. Some distros install proprietary codecs other do not. So look around try them out before installing and choose the one that best suits your daily needs. Good luck on the search and do come and tell us what you have chosen.