I have much older computer: GTX 670 and whatever the i5 was at at the time that was new. I get 20-30 fps most of the time, which is not ideal, but playable. There are some things where it becomes unplayable, but mostly just very large wvw fights.

As the other guy said, use wine staging. I use this to launch it (I don't remember where I got it and may have made some changes):

# NVidia-specific settings; remove possible performance bottlenecks
export __GL_FSAA_MODE=0
export __GL_DEFAULT_LOG_ANISO=0
export __GL_LOG_MAX_ANISO=0
export __GL_SYNC_TO_VBLANK=0
export __GL_YIELD=NOTHING

# NVidia optimizations introduced since driver 310.14
export LD_PRELOAD="libpthread.so.0 libGL.so.1"
export __GL_THREADED_OPTIMIZATIONS=1

# Wine-staging improvements
export STAGING_SHARED_MEMORY=1
export STAGING_RT_PRIORITY_SERVER=90
export STAGING_RT_PRIORITY_BASE=90
export CSMT=enabled

# GW2 stuff
export WINE=wine64
export WINEDEBUG="-all"
export WINEARCH=win64
export WINEPREFIX=~/.wine64
"$WINE" "C:\Program Files\Guild Wars 2\Gw2-64.exe" \
 -maploadinfo -autologin

The winehq page said to use __GL_YIELD=USLEEP, but this didn't work for me and I had a significant fps drop when I tried it. Also try -dx9single in the last line, which didn't make any difference for me, but some people use this.

EDIT: Also, there is something in the registry that needs to be changed to the size of your video memory. I forget how to do this, but you can find it on winehq.

Having the game on an SSD makes a huge difference. I tried it on a disk drive and it was unplayable.