So the title pretty much sums it up but here is as much detail as I can give.
The game runs great for a while. Then suddenly the screen will go black and when it comes back the game will run very laggy.
The only way I have found to fix this is to exit out of the game and start it back up.
I'm on PC.
Thank you for submitting your report about [description of the bug]. We appreciate that you have taken time out of your day and away from playing FINAL FANTASY XIV: A Realm Reborn to let us know about this trouble so we can improve the experience of playing the game.
While we do appreciate that you have brought our attention to the trouble you experienced, the amount of information provided is insufficient for us to conduct an investigation into the cause of the trouble and how we can resolve it. To help provide some insight into the information we find valuable for looking into and resolving these errors, you can go to the Welcome to the "In-Game Bugs" Forum! (READ THIS FIRST) to find out what information we do need and why that information is important. There are also templates that we provide for reporting Windows errors and PS3 errors. We are certainly not going to require strict adherence to the templates, but they do help show the information we find important for those reports in an easy to fill out format. As long as the information is provided, however, feel free to use the format that feels most comfortable and informative to you.
We are looking forward to getting more information from you so we can look into this error and try to resolve it. Thank you for taking the time to provide more information about this error, and thank you for playing FINAL FANTASY XIV: A Realm Reborn.