I’ve had the same issues since yesterday.
Normally I’d get around 46-50 FPS and maybe 13 Ping at medium settings (Geforce 710m) and since the update I get major framedrops to around 11 FPS even at lowest settings and my Ping is on average 300-400 with spikes of up to 1400.
External tests show my Ping is about 14 on average and Just GW2 has these problems.
I’d very much like to know where the problem lies and what we should do.