My system specs:
Dell XPS L702X with:
Intel Core i7 2670QM 2,20Ghz
RAM: 8gb
Gfx: Nvidia Geforce GT 555M
all with latest possible drivers (graphic card updated to recomended by GW2 launcher 304 beta drivers)
Normally game runs great (45-50fps) on auto-detected graphic options (medium-high settings) but on world boss fights (like Shatterer) fps is droping to 10 and huge lag occurs (almost unabling to use utility/elite skills).