Upgrading your card to 300/300 is going to give you the same problems simply based on CSMA/CA. Trying to view the folder with previews is both ridiculous as well as too bandwidth intensive for the setup you want to use. Higher bitrate 720p and 1080p videos will still lag and stutter.
You can keep asking or being rude to people until someone says "YES, IT WILL BE AMAZING! ", even though that is the answer you are painstakingly looking for, it is not reality.
Everything on each of your PCs is irrelevant based on a larger degree of wireless problems. Looking a RAM is a waste of time, looking at page file is a waste of time, looking at HDD/SSD is a waste of time. If the video plays OK locally then it's clearly a network related issue. Given that you are using a 'turd-grade' setup, it's to be expected.
You can keep asking or being rude to people until someone says "YES, IT WILL BE AMAZING! ", even though that is the answer you are painstakingly looking for, it is not reality.
Everything on each of your PCs is irrelevant based on a larger degree of wireless problems. Looking a RAM is a waste of time, looking at page file is a waste of time, looking at HDD/SSD is a waste of time. If the video plays OK locally then it's clearly a network related issue. Given that you are using a 'turd-grade' setup, it's to be expected.