Since last few patch GW2 on my 2012 iMac run like trash. Very low FPS 20-25 in medium busy area. Many problem with graphics messed up. This example of problem I had many times.
https://forum-en.gw2archive.eu/forum/support/support/MAC-New-problem-with-graphics/first#post5415294
I decide to run it with boot camp Windows 7. So I install it and now GW2 is very good. I get 50-65 FPS in areas like DR and LA on most medium setting. About 30 FPS with busy boss fight. It looks so amazing. Like a new game I never have seen.
Here is what I did. I install Windows 7 with boot camp. Not too hard to do Internet has instruction. There is small trick. When it ask to install apple driver during boot camp do not use that. The new one cause install problem. I download driver from website instead. Instruction on the apple website on how to do this. I set partition of 150GB much more than need but if I want to play other games later. Pick right partition size because can not change later unless start over. When done install graphic card driver in Windows so it work with card. Change power setting in Windows to high for more FPS.
Playing Windows boot camp look so much better. No problem at all. It is amazing like a new fancy game it look so good. I only use boot camp for GW2. Nothing else. I do not like Windows and virus so I add Avast to be safe. My iMac has Nvidia graphic card so I do not no how it look with other card.
I suggest this. No more broken mac client. Also you will need flash drive at least 16GB to do boot camp install. The flash drive will erase so do not have things in it you want.
I hope this help some that are tired of broken mac client terrible FPS and bug. I am busy person but send message if you have question. I will help if I can. 
(edited by Qugi.2653)