Hello all! I am writing here to just issue a general PSA about WoW and 8.3. If you are having severe frame rate drops immediately after downloading the patch, check your memory (RAM) usage.
8.3 appears to be using more RAM than before, and multiple people in my guild who were only running 8 GB are running out and hitting their page files (your page file is located on your hard drive used for virtual memory and is significantly, like more than 5x slower than your physical memory). This will be significantly more common if you are running a store-bought gaming rig or a laptop, as less memory is one of the most common cost cutting measures.
If you are having frame rate drops, you can check this on Windows 10 by: opening Task Manager by right clicking on your taskbar, and clicking on Open Task Manager. From there, click on the performance tab at the top, and look at your memory while wow is open. If you are anywhere above 7.5 GB and are having frame rate issues since 8.3, this is most likely the culprit (other reasons may exist, this will just undoubtedly be very common since 8.3 appears to be eating more memory). The easiest solution if you are indeed doing this is lowering your view distance and other memory hogging graphics settings. Even if you have a top tier GPU, if you run out of RAM, your performance will tank.
Adding more memory is easy, you can check your available slots in that same memory menu in Windows 10 along with type, just be aware you will use different types (DDR3 vs DDR4) as well as different form factors (DIMM (normal sized) vs SODIMM (laptop or small form factor PCs)). Anybody with a basic analysis of PC building could help you determine compatible upgrades.
I hope this helps people who have been crashing or having frame rate issues as of the patch.