Currently, before the last update (with the music) my system would completely die when you activated a skill.
Specs of my system are:
MSI Radeon 7990
Intel Core i7 3960X
GSKILL 64GB 2400Mhz Ram
256GB SATA-3 Corsair SSD
2x3TB Raid 0 SATA-3 7200rpm
Windows 7 Ultimate 64bit
Luckily after the last update, the lag when using skills stopped (had a lot of frustration dealing with ranger skills beforehand), and the game is playable, with some minor bugs (walking through walls, etc.). I don't think I've run into any performance issues yet so far in the new update, aside from the weird bugs.
